JP6236360B2 - Construction body strength management method and construction body strength management system - Google Patents

Description

  The present invention relates to a strength management method for a construction body including a material that hardens over time, and a strength management system for the construction body.

  Patent Document 1 describes a strength characteristic measurement method for measuring the strength characteristics of a ground material at an original position. In this method, the rigid body is dropped from a certain height, and an acceleration waveform generated when the rigid body collides with the ground is acquired. Then, using the acceleration waveform and a theoretical formula based on the Hertz impact theory, the strength characteristics of the ground are calculated. According to this method, the strength characteristics of various ground materials at the original position can be accurately and efficiently measured.

JP 2009-228352 A

Takanari Yamazaki, Masao Yamada, “Basic theory of landslide analysis by FEM”, Journal of the Japan Landslide Society, Vol. 41, no. 1, pp. 74-77 (2004).

  Some materials for constructing a construction body have strength characteristics that change with the passage of time after the material is formed, and exhibit the designed strength characteristics after a lapse of a predetermined time. When the construction body is constructed with such a material, the strength characteristics of the construction body are managed with the strength characteristics after the elapse of a predetermined set time.

  This set time may range from hours to days. However, from the point of view of the construction period at the construction site, it is difficult to interrupt the construction for several days in order to manage the strength characteristics. Therefore, the construction may be continued without waiting for the set time to elapse. If it does so, when the intensity | strength characteristic after setting time passage does not satisfy | fill specification, since repair construction is needed, there exists a possibility that the construction period of a construction body may become long.

  Therefore, the present invention predicts whether or not the strength characteristic after the strength management time elapses satisfies the management threshold value, whereby the construction body strength management method and construction body strength management system capable of suppressing the lengthening of the construction period. I will provide a.

  One embodiment of the present invention is a strength management method for a construction body including a material that hardens with the passage of time. The strength management method of the construction body consists of a preparation process that prepares a management reference function including the relationship between the strength of the material and the elapsed time, and the mass body is made to collide with the construction body after the strength acquisition time elapses from the construction body construction. A waveform acquisition step for obtaining a waveform of acceleration applied to the mass body, and a measured strength calculation step for obtaining the measured strength of the construction body at the strength acquisition time by applying the acceleration waveform as an input condition to a theoretical formula based on Hertz's impact theory. Whether or not the strength of the construction body after the construction body has been subjected to a strength management time longer than the strength acquisition time satisfies a predetermined threshold using the management reference function, the strength acquisition time, and the actually measured strength Determining step.

In this construction body strength management method, first, a management reference function is prepared in a preparation process. The management reference function indicates the relationship between the strength of the material included in the construction body and the elapsed time. Next, a waveform acquisition step is performed to acquire a waveform of acceleration generated when the mass body collides with the construction body. Next, the measured intensity at the intensity acquisition time is calculated by applying the acceleration waveform to the theoretical formula based on the Hertz impact theory. According to this step, since the strength of the construction body can be directly measured at the original position, a highly accurate value can be obtained.
And in a determination process, it is determined whether the intensity | strength of the construction body after intensity | strength management time progress satisfies a threshold value. According to this process, it is possible to determine whether or not the strength of the construction body after the strength management time elapses satisfies the threshold without waiting for the strength management time longer than the strength acquisition time. Therefore, the construction can be continued without waiting for the strength management time to elapse in order to evaluate the strength of the construction body. In addition, when it is predicted that the strength of the construction body after the strength management time has not passed, it is possible to perform a necessary treatment in the strength acquisition time. Therefore, since the period required for repair is shortened, the lengthening of the construction period can be suppressed.

  The determination step includes a management reference strength calculation step for obtaining the management reference strength using the management reference function and the strength acquisition time, and a comparison step for comparing the measured strength and the management reference strength with each other. In the process, when the actually measured strength is equal to or higher than the management reference strength, it is determined that the strength of the construction body after the strength management time has passed satisfies a predetermined threshold value. According to this configuration, it is possible to easily determine whether the strength of the construction body after the strength management time elapses exceeds a threshold value.

  The management reference function is prepared based on an intensity characteristic function indicating the relationship between the strength of the material and the elapsed time, and passes through a range that is greater than or equal to a predetermined threshold in the intensity management time and less than or equal to the estimated intensity in the management time. The estimated intensity is an intensity when the intensity management time is applied to the intensity characteristic function. According to this configuration, it is possible to consider variations in material properties included in the construction body. Therefore, the accuracy of determination can be increased.

  The material may be a soil material mixed with an improving material that hardens with time, and the construction body may be ground.

  Another embodiment of the present invention is a strength management system for a construction body that includes a material that hardens over time. The construction body strength management system consists of an impact application unit with an accelerometer attached to the mass body, and an acceleration waveform obtained by the accelerometer by colliding the mass body with the construction body after the strength acquisition time has elapsed since the construction body construction. And a data processing unit for processing. The data processing unit is a management reference function recording unit that stores the management reference function including the relationship between the strength of the material and the elapsed time, and the acceleration waveform is applied as an input condition to the theoretical formula based on the Hertz impact theory to obtain the strength. Using the measured strength calculation unit that obtains the measured strength of the construction body in time, the management reference function, the strength acquisition time, and the measured strength, after the construction management of the construction body has passed a strength management time longer than the strength acquisition time And a determination unit that determines whether the strength of the construction body satisfies a predetermined threshold value.

In this construction body strength management system, the management reference function recording unit records the management reference function. The management reference function indicates the relationship between the strength of the material included in the construction body and the elapsed time. Next, the mass body is caused to collide with the construction body using the impact application unit, and the waveform of the acceleration generated by the collision is acquired using the waveform input unit. Then, the measured intensity calculation unit calculates the measured intensity at the intensity acquisition time by applying the acceleration waveform to the theoretical formula based on the Hertz impact theory. According to these configurations, since the strength of the construction body can be directly measured at the original position, a highly accurate value can be obtained.
And in a determination part, it is determined whether the intensity | strength of the construction body after progress of intensity management time satisfy | fills a threshold value. According to this process, it is possible to determine whether or not the strength of the construction body after the strength management time elapses satisfies the threshold without waiting for the strength management time longer than the strength acquisition time. Therefore, the construction can be continued without waiting for the strength management time to elapse in order to evaluate the strength of the construction body. In addition, when it is predicted that the strength of the construction body after the strength management time has not passed, it is possible to perform a necessary treatment in the strength acquisition time. Therefore, since the period required for repair is shortened, the lengthening of the construction period can be suppressed.

  The determination unit includes a management reference strength calculation unit that obtains a management reference strength using the management reference function and the strength acquisition time, and a comparison unit that compares the measured strength and the management reference strength with each other. In the section, when the actually measured strength is equal to or higher than the management reference strength, it is determined that the strength of the construction body after the lapse of the strength management time satisfies a predetermined threshold. According to this configuration, it is possible to easily determine whether the strength of the construction body after the strength management time elapses exceeds a threshold value.

  The management reference function is prepared based on an intensity characteristic function indicating the relationship between the strength of the material and the elapsed time, and passes through a range that is greater than or equal to a predetermined threshold in the intensity management time and less than or equal to the estimated intensity in the management time. The estimated intensity is an intensity when the intensity management time is applied to the intensity characteristic function. According to this configuration, it is possible to consider variations in material properties included in the construction body. Therefore, the accuracy of determination can be increased.

  The material may be a soil material mixed with an improving material that hardens with time, and the construction body may be ground.

  According to the construction body strength management method and construction body strength management system of the present invention, it is possible to suppress the lengthening of the construction period by predicting whether the strength characteristics after the strength management time elapses satisfy the management threshold. be able to.

It is a flowchart which shows the process of the strength management method of the construction body which concerns on this invention. It is a detailed flowchart which shows the intensity | strength confirmation process shown by FIG. It is a graph which shows the relationship between a deformation coefficient and uniaxial compressive strength. It is a graph which shows the relationship between age and a deformation coefficient. It is a graph which shows the actual measurement value and strength characteristic curve of uniaxial compressive strength. It is a graph which shows an intensity | strength characteristic curve and a control reference curve. It is a graph which shows a control standard curve and measured uniaxial compressive strength. It is a figure which shows the structure of the intensity | strength management system of the construction body which concerns on this invention. It is a figure which shows the structure of the computer shown by FIG. It is a functional block diagram which shows the structure of the intensity | strength management system of the construction body which concerns on this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  As a result of intensive studies by the inventors, the strength of the construction body including the material has a certain degree of reproducibility over time. Thus, it has been found that by obtaining the relationship between time and strength in advance, it is possible to predict whether the strength changes at a predetermined age by predicting a change in strength or not. For example, according to the strength management method of the construction body and the strength management system of the construction body, it is determined whether the ground strength on the 28th day of the age satisfies the management threshold by using the ground strength on the 5th day of the age. It is possible. Hereinafter, the strength management method of the construction body and the strength management system of the construction body that evaluates whether the strength at the predetermined age of the construction meets the management threshold using the strength of the construction body at the young age will be described in detail. explain.

  In the following description, an embodiment for carrying out the present invention will be described by taking the strength management of the ground as an example. Such a ground includes a water-cured material that hardens by reacting with moisture, a time-cured material that hardens with time, and the like. More specifically, in the construction of the ground, an improved soil whose properties are improved by mixing an improved material such as an inorganic flocculant, cement, cement-based solidifying agent, slag and the like may be used.

  As shown in FIG. 1, the construction body strength management method includes a preparatory step S10 that is performed in advance before actual strength confirmation, and a strength confirmation step S20 that is performed at the construction site. In the preparation step S10, a management reference function including the relationship between the strength of the material constituting the ground and time is acquired. Then, using the management reference function acquired in the preparation step S10, it is evaluated whether or not the strength characteristic at a predetermined material age satisfies the management threshold from the strength characteristic at the young material age.

  Here, the falling ball exploration test used for the strength management method of the construction body will be described. As described in Patent Document 1, the falling ball exploration test is a technique in which an aluminum sphere with a built-in accelerometer is dropped from a certain height, and the deformation coefficient of the ground is instantaneously measured from the measured waveform based on the plastic deformation theory. It is. In general, there is a correlation between the deformation coefficient of the ground and the uniaxial compressive strength (Non-Patent Document 1), and this relationship can be introduced into a measurement system for a falling ball exploration test, and the strength can be calculated from the deformation coefficient. Expanded to technology. In addition, it is possible to predict the uniaxial compressive strength at each age by grasping the strength increase characteristics of the improved soil during indoor blending tests and test construction.

  The deformation coefficient means a deformation amount when a force is applied to the soil material, and is a coefficient corresponding to a so-called Young's modulus. The deformation coefficient is calculated from a theoretical formula based on the Hertz impact theory. In this calculation method, the weight 3 is freely dropped and the contact time with the ground 13 is measured. Then, based on the contact time, the deformation characteristics of the ground are calculated from a theoretical formula based on the Hertz impact theory.

According to Hertz's impact theory, the contact time Tc between the falling sphere (for example, the weight 3) and the elastic body plane (for example, the ground) is: (1) Deformation characteristics of the sphere (Young's modulus E ₁ and Poisson's ratio μ ₁₎ ), (2) Deformation characteristics of the elastic body plane (Young's modulus E ₂ and Poisson's ratio μ ₂ ), (3) Sphere mass M ₁ , sphere radius R _1, and drop height h.

ここで、δ_ｉ＝（１−μ_ｉ ^２）／（Ｅ_ｉπ）（ｉ＝１，２）である。また、ｇは重力加速度であり、ｇ＝９．８（ｍ／ｓ^２）である。 When a sphere having a mass M ₁ and a radius R ₁ is dropped from the drop height h onto the elastic body plane, the contact time Tc between the sphere and the elastic body plane is expressed by Expression (1).

Here, δ _i = (1−μ _i ² ) / (E _i π) (i = 1, 2). Further, g is a gravitational acceleration, and g = 9.8 (m / s ² ).

From the equation (1), the contact time Tc between the sphere and the elastic body plane is the sphere mass M ₁ , the sphere radius R ₁ , the drop height h, the deformation characteristics of the sphere (Young's modulus E ₁ and Poisson's ratio μ ₁ ), It can also be seen that it is determined by the deformation characteristics of the elastic body plane (Young's modulus E ₂ and Poisson's ratio μ ₂ ). The contact time Tc can be obtained from the acceleration waveform, and includes the mass M _{1 of} the sphere, the radius R _{1 of} the sphere, the drop height h, the deformation characteristics of the sphere (Young's modulus E ₁ , Poisson's ratio μ ₁ ), and the elastic body plane. Since the deformation characteristic (Poisson's ratio μ ₂ ) is already known, the unknown amount is the deformation characteristic (Young's modulus E ₂ ) of the elastic body plane. Therefore, if the elastic body plane having the same deformation characteristics is dropped once, the deformation characteristics (Young's modulus E ₂ ) of the elastic body plane can be estimated.

The preparation step S10 includes a first step S11 for obtaining a function indicating the relationship between the deformation coefficient and the uniaxial compression strength qu, the deformation coefficient E _D obtained by the falling ball exploration test, and the deformation coefficient E ₅₀ obtained by the uniaxial compression test. Used in the second step S12 for obtaining a coefficient indicating the relationship between the first step, the third step S13 for obtaining a function indicating the relationship between the uniaxial compressive strength qu and the material age for constructing the ground, and the strength confirmation step S20. And a fourth step S14 for obtaining a management reference curve.

In a first step S11, it acquires the relationship between the modulus of deformation E ₅₀ of the modified soil with unconfined compressive strength qu. More specifically, in the first step S11, the result of blending tests and test construction of improved soil, and calculates the relationship between the deformation coefficient E ₅₀ and unconfined compressive strength qu. Here, the deformation coefficient E ₅₀ refers to a value acquired by a uniaxial compression test. The deformation coefficient E _D is a value acquired by a falling ball exploration test.

なお、一軸圧縮強度ｑｕと変形係数Ｅ_５０との関係を示す関数は、式（２）のような一次関数に限定されることなく、一軸圧縮強度ｑｕと変形係数Ｅ_５０との関係を好適に示すことができる公知の関数を利用することができる。 Figure 3 shows an example of the relationship between the deformation coefficient E ₅₀ and unconfined compressive strength qu. Data P3 indicating such a relationship may be obtained by experiments or may be prepared using a known database. Then, a coefficient α in Expression (2) indicating the relationship between the uniaxial compressive strength qu and the deformation coefficient E ₅₀ is calculated from the data P. The graph shown by Formula (2) is the graph G3a in FIG.

Incidentally, a function showing a relationship between deformation coefficient E ₅₀ and unconfined compressive strength qu is not limited to a linear function of Equation (2), preferably the relationship between deformation coefficient E ₅₀ and uniaxial compressive strength qu Any known function that can be shown can be used.

In the second step S12, acquires the relationship between the deformation coefficient E ₅₀ and deformation coefficient E _D at a given wood age. The strength method for managing construction body, to obtain a deformation coefficient E _D by carrying out the falling ball exploration test. On the other hand, the intensity control method of the normal of the ground, to obtain a deformation coefficient E ₅₀ to implement a uniaxial compression test. Here, the deformation coefficient E _D obtained by performing the falling ball exploration test and the deformation coefficient E ₅₀ obtained by performing the uniaxial compression test have the same value as long as the specimens are the same. It may vary slightly depending on the conditions.

In the second step S12, firstly, it obtains the deformation coefficient E _D by carrying out the falling ball probe test on ground having a predetermined age of (e.g. age of 28 days). Then, a specimen of the falling ball exploration test from ground locations that were performed were collected to obtain a deformation coefficient E ₅₀ to implement a uniaxial compression test. Then, the correlation coefficient β is obtained by substituting the deformation coefficient E _D and the deformation coefficient E ₅₀ into Expression (3).

Then, the deformation coefficient _{E 50} of the formula (2) obtained in the first step S11, by substituting equation (3) obtained in the second step S12, the deformation coefficient _{E D} obtained by falling ball exploration test, uniaxial The following formula (4) for obtaining the compressive strength qu is obtained.

The third step S13. Acquires the relationship between the deformation coefficient _{E D} uniaxial compressive strength qu. In more detail, in 3rd process S13, test construction is implemented using the material of the same quality as the improvement soil used for construction of the ground. Then, with respect to ground up to an age of 0 - 28 during the test installation, to implement the falling ball exploration test, to obtain a deformation coefficient E _D at each timber of age. Figure 4 is a two-dimensional coordinate system with the longitudinal axis of the deformation coefficient E _D of the horizontal axis ground the material age, in which the deformation coefficient E _D plots (point P4). As shown in FIG. 4, deformation coefficient E _D of the ground it can be seen that increases as wood age increases.

Next, as shown in FIG. 5, the vertical axis is converted from the deformation coefficient E _D to the uniaxial compressive strength qu using Equation (4). And each coefficient in the intensity | strength characteristic function which shows the relationship between material age and uniaxial compressive strength qu is calculated. In the present embodiment, the hyperbolic function represented by the equation (5) is used as the intensity characteristic function. Here, a and b are coefficients, t is material age, and qu (t) is uniaxial compressive strength when material age is t.

  In addition, the relationship between age and uniaxial compressive strength qu is not limited to a hyperbolic function, and a known function can be used. The graph shown by Formula (5) is the graph G5a in FIG.

In the fourth step S14, a management reference function is acquired. That is, in the fourth step S14, the management reference function indicating the management reference curve and its coefficient are determined using the intensity characteristic function (equation (5)) acquired in the third step S13. More particularly, the variation of the deformation coefficient E _D is assumed to follow a normal distribution, to contain the results of 99.73% (i.e. ± 3 [sigma]), to determine a management reference curve.

As shown in FIG. 6, first, a standard deviation σ is calculated using a plurality of measurement points P6. Subsequently, a curve (graph G6b) that is + 3σ and a curve (graph G6c) that is −3σ are determined with respect to the strength characteristic function (see Expression (5) and graph G6a) indicating the uniaxial compressive strength qu. Between the graph G6b and the graph G6c, 99.73% of measurement data is included. Therefore, a curve (graph G6c) that is −3σ is used as a threshold for determination. This curve is represented, for example, by equation (6). Hereinafter, this curve is referred to as a management reference curve.

Referring to the management reference curve (graph G6c) and the management reference line (graph G6d) shown in FIG. 6, at the age of 28 days (672 hours), the management reference curve exceeds the management reference line. Here, the management reference line indicates a management threshold value cu _cri that should be satisfied at the age of 28 days. That is, the uniaxial compressive strength qu of the ground at the age of 28 days satisfies the management threshold value cu _cri . If the uniaxial compressive strength qu of the ground follows a change with time similar to that of the management reference curve, if the uniaxial compressive strength qu measured at each material age exceeds the management reference curve, the material age 28 The uniaxial compressive strength qu in the day can be predicted to satisfy the management threshold value cu _cri .

That is, the management reference curve (graph G6c) indicated by the management reference function is above the straight line (graph G6d) indicated by the management threshold cu _cri , and the material age 28 calculated from the strength characteristic function (formula (5)). It passes the range below the uniaxial compressive strength qu (28) (point P6b) that is the estimated strength in the day.

The width set for the intensity characteristic function is not limited to ± 3σ and may be ± 2σ. Further, the variation of the deformation coefficient E _D may be processed according to a probability distribution other than the normal distribution.

  By performing the preparatory step S10 including the first to fourth steps S11 to S14, a function (formula (6)) indicating a management reference curve including the relationship between the strength of the material constituting the ground and time is obtained. Is done.

Next, a strength confirmation step S20 for confirming the strength at the time of construction is performed. In this step S20, a falling ball exploration test is performed at an actual construction site to obtain a uniaxial compressive strength qu (t), and the uniaxial compressive strength qu (28) at the age of 28 days is determined as a control threshold using the result. It is determined whether or not _{cu cri} is satisfied. As shown in FIG. 2, this strength confirmation step S20 includes a step of acquiring a acceleration waveform by performing a falling ball exploration test (waveform acquisition step S21), and a uniaxial compression strength qu (t) using the acceleration waveform as an input condition. A step of calculating (measured strength calculating step S22) and a step of determining whether or not the uniaxial compression strength qu (t) will satisfy the management threshold value cu _{cri in the} future (determination step S23).

First, a falling ball exploration test is carried out after elapse of t days immediately after the ground construction, and an acceleration waveform is acquired. In this step S21, the acceleration waveform and the age of the ground (t days) when the falling ball exploration test is performed are acquired as a result. Subsequently, the uniaxial compression strength qu (t) is calculated using the acceleration waveform. And more particularly, to calculate a deformation coefficient E _D by utilizing the contact time resulting from the acceleration waveform (step S22a). For this calculation, a known calculation method based on Hertz's impact theory as described in Patent Document 1 (Japanese Patent Laid-Open No. 2009-228352) is used. Then, using the modified coefficients _{E D,} to calculate the uniaxial compressive strength qu (t) (step S22b).

Subsequently, it is determined whether or not the uniaxial compressive strength qu (t) calculated in step S22 satisfies the management threshold value cu _cri when the material age is 28 days (step S23). More specifically, by using the uniaxial compressive strength qu (t) when the material is t days old, it is determined whether or not the uniaxial compressive strength qu (28) of the material age 28th is equal to or higher than the management threshold value cu _cri. judge. That is, in this embodiment, the value of the uniaxial compressive strength qu (28) that can be obtained in the future is not predicted from the uniaxial compressive strength qu (t) at a predetermined age, but the uniaxial compressive strength qu ( It is determined whether or not 28) is _{equal to} or greater than the management threshold value cu _cri .

FIG. 7 shows a management reference curve (graph G7a). When the uniaxial compressive strength qu (t) at the age of material t exceeds the management reference curve, it is determined that the uniaxial compressive strength qu (28) at the age of material 28 exceeds the control threshold value cu _cri . Specifically, using the material age t day when the falling ball exploration test is performed and the management standard curve or a function (formula (6)) indicating the management standard curve, the management standard when the material age is t days calculating the intensity qu _s (control standard intensity calculation step S23a). Then, the measured uniaxial compression strength qu (t) calculated in step S22 is compared with the management reference strength qu _s (comparison step S23b).

Here, when the uniaxial compressive strength qu (t) is equal to or greater than the management reference strength qu _s, it is determined that the uniaxial compressive strength qu (28) on the 28th day of age satisfies the management threshold value cu _cri (step S23b: YES). Then, the strength determination is performed again at a predetermined timing while continuing the construction of the ground (step S24). On the other hand, when the uniaxial compressive strength qu (t) is less than the management reference strength qu _s, it is determined that the uniaxial compressive strength qu (28) on the 28th day of the age does not satisfy the management threshold value cu _cri (step S23b : NO). And the construction of the ground is temporarily interrupted (step S25), and necessary reinforcement measures are implemented for the ground.

For example, when a material age t, uniaxial compressive strength qu obtained by falling ball exploration test (t) is indicated by a point P7a, management reference intensity qu _s is indicated by a point P7b. Comparing the uniaxial compressive strength qu (t) and control standards strength qu _s, P7a point indicating the uniaxial compressive strength qu (t) is above the P7b point indicating the management reference intensity qu _s. Therefore, in this case, it is determined that the uniaxial compressive strength qu (28) at the age of 28 days satisfies the management threshold value cu _cri .

  Here, the strength management method according to the comparative example for evaluating the ground characteristics constructed with the improved soil will be described. The quality of the ground constructed by improved soil that hardens with the passage of time is managed using, for example, uniaxial compressive strength. The uniaxial compression strength is obtained by a test according to a uniaxial compression test defined in Japanese Industrial Standard (JIS-A-1216). The reason for this is that the uniaxial compressive strength enables the evaluation of ground characteristics such as durability and water permeability without requiring advanced test techniques and long test periods.

  As one of the methods for evaluating the ground characteristics using the uniaxial compression test, there is a method in which a specimen is prepared using the improved soil immediately after production, and the uniaxial compression test is performed when it is a predetermined age (28 days). is there. There is also a method of collecting a specimen from the ground of a predetermined age (28 days) and performing a uniaxial compression test.

  However, according to the method described above, the properties of the specimen may differ from the properties of the ground constructed with the actual improved soil, and the characteristics obtained by the uniaxial compression test may not accurately indicate the properties of the actual ground. is there. More specifically, when a specimen is manufactured using the improved soil immediately after production, the properties of the specimen may differ from the actual improved soil due to restrictions on the allowable maximum particle size at the time of preparing the specimen. For example, when constructing a bank with improved soil having a maximum particle size (Dmax) of 100 mm, there is no standard for specimens by tamping that allows mixing of soil with a particle size of 100 mm. Soil larger than the maximum grain size is removed. Then, the properties of the specimen and the improved soil change. Such a problem also applies to specimens manufactured by methods other than tamping. Furthermore, the uniaxial compressive strength of the ground constructed with improved soil depends on the degree of compaction. However, it is difficult to say that it is a realistic method because it takes a lot of labor to make the compaction degree of the specimen equal to that of the ground.

  Further, the method described later is considered to be effective as a method for performing a uniaxial compression test in order to collect a specimen from the actual ground. However, when the maximum particle size of the improved soil is increased, the degree of difficulty required for obtaining the specimen increases, and an operator having a skilled boring technique is required. Furthermore, the ground with improved soil is constructed in layers. Then, depending on the construction environment, a younger age layer is laminated on the 28th day age layer, so it is difficult to collect a specimen from the 28th day age layer. In addition, the uniaxial compression test is difficult to implement in the first place when the material is young.

  In contrast to the method according to the comparative example, in the strength management method and the strength management system of the present embodiment, the ground actually constructed with improved soil is used as a measurement target. Therefore, there is no change in the properties of the specimen due to the allowable maximum particle size during specimen preparation. Therefore, according to the strength management method and the strength management system of the present embodiment, the uniaxial compressive strength qu (t) of the ground constructed with the improved soil can be accurately measured at the original position.

In addition, it is possible to predict whether or not the subsequent strength satisfies the management threshold value cu _cri using the measured uniaxial compression strength qu (t). Therefore, according to the strength management method and the strength management system of the present embodiment, the uniaxial compressive strength qu (t) of the ground constructed with the improved soil can be accurately and efficiently evaluated at the original position. Furthermore, quality troubles can be found and dealt with early.

  Moreover, anyone can carry out the strength management method of the present embodiment easily and quickly. Therefore, it is possible to prevent the construction from being interrupted for a long time without requiring a skilled engineer.

  More specifically, in this construction body strength management method, first, a management reference function is prepared in the preparation step S10. The management reference function indicates the relationship between the strength of the material contained in the ground as the construction body and the elapsed time. Next, the waveform acquisition step S21 is performed to acquire a waveform of acceleration generated when the mass body collides with the ground. Next, the acceleration waveform is applied to a theoretical formula based on the Hertz impact theory to calculate the uniaxial compressive strength qu (t) during the falling ball exploration test. According to the steps S21 and S22, since the strength of the ground can be directly measured at the original position, a highly accurate value can be obtained.

And in intensity | strength confirmation process S20, it is determined whether the uniaxial compressive strength qu (28) of the ground body in material age 28 satisfy _| fills the management threshold value _cucri . According to the strength confirmation step S20, it is determined whether or not the future ground strength satisfies the management threshold value cu _cri without waiting for the elapse of a period longer than the period when the falling ball exploration test is performed from the time of construction. Is possible. Therefore, it is possible to continue the construction without waiting for the passage of time in order to evaluate the strength of the ground. In addition, if it is predicted that the strength of the ground will not be satisfied, it becomes possible to perform necessary treatment immediately after the falling ball exploration test is performed. Therefore, since the period required for repair is shortened, the lengthening of the construction period can be suppressed.

Moreover, according to determination process S23, it can be easily determined whether the intensity _| strength of the ground in material age 28 day exceeds the management threshold value _cucri .

  The management reference curve has a width of −3σ with respect to the strength characteristic function indicating the strength characteristics of the material. According to this function, it is possible to take into account variations in material characteristics included in the ground. Therefore, the accuracy of determination can be increased.

  Moreover, since the strength management method of the construction body according to the present embodiment uses the falling ball exploration test, the test can be performed even when the material constituting the ground is young.

  Moreover, in the strength management method of the construction body, it is possible to evaluate the strength at the original position. For this reason, it is not necessary to extract the specimen as in the case of carrying out the uniaxial compression test. Therefore, strength management can be performed even in places where it is difficult to collect specimens, such as construction bodies constructed in water.

  Next, a system for carrying out the construction body strength management method described above will be described. The strength management system of a construction body obtains the strength characteristics of the ground using an acceleration waveform obtained by causing a heavy object to collide with the ground. As shown in FIG. 8, the construction body strength management system 1 includes a weight 3 having an accelerometer 2, a charge amplifier 4 connected to the accelerometer 2, and a terminal panel connected to the charge amplifier 4. 6, an A / D conversion device 7 connected to the terminal panel 6, and a computer 8 connected to the A / D conversion device 7.

  More specifically, the weight 3 and the accelerometer 2 constitute an impact applying unit 9. The charge amplifier 4, the terminal panel 6, and the A / D converter 7 constitute a waveform input unit 11. The computer 8 includes a data processing unit 12 (see FIG. 10).

  The weight 3 is caused to fall and collide with the ground 13 to be measured. The weight 3 has a mass of, for example, 19.1 kg, and is dropped perpendicularly to the ground 13 from a height of 50 cm. That is, the moving direction of the weight 3 is substantially the normal direction of the ground 13. The charge amplifier 4, the terminal panel 6, and the A / D conversion device 7 acquire an acceleration waveform that acts on the weight 3 due to the falling collision of the weight 3 and inputs it to the computer 8.

  FIG. 9 is a diagram illustrating a hardware configuration of the computer 8. The computer 8 includes various data processing devices such as a server device that includes a CPU and performs processing and control by software, and a personal computer. As shown in FIG. 9, a computer 8 includes a reading device 8a such as a floppy (registered trademark) disk drive device, a CD-ROM drive device, a DVD drive device, and a working memory (RAM) 8b in which an operating system is resident. A memory 8d for storing a program stored in the recording medium 8c, a display device such as a display 8e, a mouse 8f and a keyboard 8g as input devices, a communication device 8h for transmitting and receiving data, etc. CPU8j which controls execution. When the recording medium 8c is inserted into the reading device 8a, the computer 8 can access the program stored in the recording medium 8c from the reading device 8a, and can operate as the data processing unit 12 by the program. Become.

The data processing unit 12 performs predetermined processing using the input acceleration waveform. More specifically, the uniaxial compressive strength qu (t) of the material age t day is obtained using the input acceleration waveform, and the uniaxial compressive strength qu (t) of the material age 28 day is obtained using the uniaxial compressive strength qu (t). It is determined whether or not the compression strength qu (28) satisfies the management threshold value cu _cri .

As shown in FIG. 10, the data processing unit 12 includes an actually measured intensity calculation unit 12a, a management reference function recording unit 12b, and a determination unit 12c. Found intensity calculation unit 12a executes a step S22a of calculating a deformation coefficient _{E D,} and a step S22b to calculate a uniaxial compressive strength qu (t). The actually measured intensity calculation unit 12 a is connected to the A / D conversion device 7 of the waveform input unit 11, and digitized acceleration data is input from the A / D conversion device 7. In addition, the actual strength data obtained when the test is performed from the input device 14 such as the mouse 8f and the keyboard 8g connected to the data processing unit 12 is input to the actually measured strength calculating unit 12a. The actually measured strength calculating unit 12a calculates the uniaxial compressive strength qu (t) as the actually measured strength using these acceleration data and material age data, and outputs the calculated uniaxial compressive strength qu (t) to the determining unit 12c.

Information related to the management reference function is recorded in the management reference function recording unit 12b and can be referred to from the determination unit 12c. For example, the information related to the management criterion function includes a function (see equation (6)) indicating the management criterion function and a coefficient value thereof, a database in which the age and the management threshold value cu _cri are associated with each other. Information regarding these management reference functions may be input from the input device 14, or may be read from the information recorded on the recording medium 8c via the reading device 8a.

  Further, before the process S20, the strength management system 1 of the construction body is used to acquire the ground strength at each age, and the management reference function recording unit 12b performs a predetermined process to obtain information on the management reference function. You may get According to such a configuration, the management reference function is updated at a predetermined timing, so that the prediction accuracy can be improved. Further, the management reference function recording unit 12b may record data related to the place where the impact is applied.

The determination unit 12c uses the uniaxial compressive strength qu and the management criterion function (equation (6)) to determine the uniaxial compressive strength qu on the 28th day of ages from the uniaxial compressive strength qu (t) on the age t. It is determined whether (28) satisfies the management threshold value cu _cri . That is, the determination unit 12c includes a management reference strength calculation unit 12e and a comparison unit 12f, and performs step S20. Then, a determination result that the uniaxial compression strength qu (28) satisfies the management threshold value cu _cri or the uniaxial compression strength qu (28) does not satisfy the management threshold value cu _cri is output to the display device 16 such as the display 8e and displayed. . The determination unit 12c is connected to the actually measured strength calculation unit 12a and receives the uniaxial compression strength qu (t). Further, the determination unit 12c is connected to the management reference function recording unit 12b and receives information related to the management reference function.

  In the strength management system 1 of the construction body, information on the management reference curve is recorded in the management reference function recording unit 12b. The management reference function indicates the relationship between the strength of the material contained in the ground 13 and the elapsed time. Next, the weight 3 is caused to collide with the ground 13 using the impact applying unit 9, and the waveform of the acceleration generated by the collision is acquired using the accelerometer 3 and the waveform input unit 11. Then, the measured strength calculation unit 12a calculates the uniaxial compressive strength qu (t) at a predetermined time by applying the acceleration waveform to the theoretical formula based on the Hertz impact theory. According to these configurations, since the uniaxial compressive strength qu (t) of the ground 13 can be obtained by directly measuring at the original position, a highly accurate value can be obtained.

Then, the determination unit 12c determines whether or not the uniaxial compression strength qu (28) at the age of 28 days satisfies the management threshold value cu _cri using the uniaxial compression strength qu (t) of the ground 13. According to the determination unit 12c, it is possible to determine whether or not the uniaxial compression strength qu (28) of the ground 13 after a predetermined period has passed satisfies the management threshold value cu _cri . Therefore, the construction can be continued without waiting for the elapse of a predetermined period in order to evaluate the uniaxial compressive strength qu (28) of the ground 13. In addition, if it is predicted that the uniaxial compressive strength qu (28) of the ground 13 after the lapse of the predetermined period is not satisfied, it is possible to perform necessary treatment without waiting for the lapse of the predetermined period. Therefore, since the period required for repair is shortened, the lengthening of the construction period can be suppressed.

In addition, the determination unit includes a management reference strength calculation unit 12e that obtains the management reference strength by applying the strength acquisition time to the management reference function, and a comparison unit 12f that compares the actually measured strength with the management reference strength. When the actually measured strength is equal to or higher than the management reference strength, the comparison unit 12f determines that the uniaxial compressive strength qu (28) of the ground 13 after the strength management time has elapsed satisfies the management threshold value cu _cri . According to this configuration, it is possible to easily determine whether or not the qu (28) of the ground 13 after the strength management time elapses exceeds the management threshold value cu _cri .

In addition, the management reference function is prepared based on an intensity characteristic function indicating the relationship between the strength of the material and time, and passes through the range of the management threshold value cu _cri and the estimated strength or less in the strength management time. The estimated intensity is an intensity when the intensity management time is applied to the intensity characteristic function. According to this configuration, it is possible to take into account variations in material characteristics included in the ground 13. Therefore, the accuracy of determination can be increased.

Moreover, according to the determination part 12c, it can be easily determined whether the intensity _| strength of the ground in material age 28 day exceeds the management threshold value _cucri .

  In addition, the management reference curve recorded in the management reference function recording unit 12b has a width of −3σ with respect to the strength characteristic function indicating the strength characteristic of the material. According to this function, it is possible to take into account variations in material properties included in the ground 13. Therefore, the accuracy of determination can be increased.

  The present invention is not limited to the above-described embodiment, and various modifications as described below are possible without departing from the gist of the present invention.

  In step S14 of acquiring the management reference curve, the same variation width (−3σ) was set for the strength characteristic function over the entire range of material ages, and a management reference curve was obtained. As the width of the variation, a different width may be set for each predetermined age.

Further, the intensity managing construction body has obtained a deformation coefficient E _D by carrying out the falling ball exploration test. In the falling ball exploration test, in addition to dropping the weight 3 along the normal direction of the ground 13, an impact may be applied to the ground 13 so as to be inclined with respect to the normal direction. For example, the weight 3 may be caused to collide obliquely with the ground that is a horizontal plane, or the weight 3 may be caused to fall and collide with the ground that is a slope in the vertical direction.

In addition, the construction body strength management system may acquire an acceleration waveform acting in each direction by placing a triaxial accelerometer on the weight 3. According to this arrangement, it becomes possible to calculate the collision direction of the weight 3 against the ground, it is possible to improve the accuracy of calculation of the deformation coefficient E _D.

  The strength management system of the construction body may acquire the acceleration waveform generated by the collision of the weight 3 with the ground 13, and may record the position of the collision of the weight 3 with the ground 13 by GPS or the like.

  Further, the falling ball exploration test is not limited to being performed in the atmosphere, and may be performed in water.

DESCRIPTION OF SYMBOLS 1 ... Strength management system, 2 ... Accelerometer, 3 ... Weight, 4 ... Charge amplifier, 6 ... Terminal panel, 7 ... A / D converter, 8 ... Computer, 9 ... Impact application part, 11 ... Waveform input part, 12 ... data processing unit, 12a ... measured intensity calculator, 12b ... control criterion function recording unit, 12c ... determining unit, 13 ... ground, E _{50 ...} deformation coefficient by uniaxial compression test, deformation coefficient by E D _... falling ball exploration test, S10: Preparation step, S20: Strength confirmation step, S21: Waveform acquisition step, S22: Measured strength calculation step, S23: Determination step, cu: Uniaxial compression strength, t ... Material age, Uniaxial compression strength at day t, qu (28 ) ... uniaxial compressive strength at age 28 days, cu _cri ... control threshold.

Claims (8)

In the strength management method of the construction body containing the material that hardens with time,
Preparing a management reference function including a relationship between the strength of the material and the elapsed time;
After the elapse of the strength acquisition time from the construction of the construction body, a waveform acquisition step of obtaining a waveform of acceleration applied to the mass body by colliding the mass body with the construction body;
Applying the waveform of acceleration to a theoretical formula based on Hertz's impact theory as an input condition, and obtaining a measured strength of the construction body at the strength acquisition time,
Using the management reference function, the strength acquisition time, and the measured strength, the strength of the construction body after the construction management body has passed a strength management time longer than the strength acquisition time has a predetermined threshold value. A determination process for determining whether or not the construction body is satisfied. The determination step includes
A management reference strength calculation step for obtaining a management reference strength using the management reference function and the strength acquisition time;
A comparison step of comparing the measured intensity and the management reference intensity with each other,
The construction according to claim 1, wherein, in the comparison step, when the measured strength is equal to or higher than the management reference strength, it is determined that the strength of the construction body after the strength management time has passed satisfies a predetermined threshold value. Body strength management method. The management reference function is prepared based on an intensity characteristic function indicating a relationship between the strength of the material and the elapsed time, and has a range of not less than the predetermined threshold and not more than an estimated intensity in the management time in the strength management time. Street,
The said estimated intensity | strength is a intensity | strength management method of the construction body of Claim 1 or 2 which is an intensity | strength when the said intensity | strength management time is applied to the said intensity | strength characteristic function. The material is a soil material mixed with an improving material that hardens over time,
The strength management method for a construction body according to any one of claims 1 to 3, wherein the construction body is a ground. In the strength management system for construction bodies containing materials that harden over time,
An impact applying unit having an accelerometer attached to the mass body;
A data processing unit that processes an acceleration waveform obtained by the accelerometer by causing the mass body to collide with the construction body after the elapse of strength acquisition time from construction of the construction body,
The data processing unit
A management criterion function recording unit for storing a management criterion function including the relationship between the strength of the material and the elapsed time;
Applying the waveform of acceleration as an input condition to a theoretical formula based on Hertz's impact theory, an actual strength calculation unit for obtaining the actual strength of the construction body at the strength acquisition time;
Using the management reference function, the strength acquisition time, and the measured strength, the strength of the construction body after the construction management body has passed a strength management time longer than the strength acquisition time has a predetermined threshold value. A strength management system for a construction body, comprising: a determination unit that determines whether or not the condition is satisfied. The determination unit
A management reference strength calculation unit that obtains a management reference strength using the management reference function and the strength acquisition time;
A comparison unit that compares the measured intensity and the management reference intensity with each other;
The construction according to claim 5, wherein the comparison unit determines that the strength of the construction body after a lapse of the strength management time satisfies a predetermined threshold when the measured strength is equal to or greater than the management reference strength. Body strength management system. The management reference function is prepared based on an intensity characteristic function indicating a relationship between the strength of the material and the elapsed time, and has a range of not less than the predetermined threshold and not more than an estimated intensity in the management time in the strength management time. Street,
The strength management system for a construction body according to claim 5 or 6, wherein the estimated strength is a strength when the strength management time is applied to the strength characteristic function. The material is a soil material mixed with an improving material that hardens over time,
The construction body is the ground,
The intensity | strength management system of the construction body as described in any one of Claims 5-7.

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