JP3721091B2 - Reinforced structure for residential ground and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reinforcing structure for a residential ground and a construction method thereof, and in particular, a soft ground layer of a residential ground caused by a built-up ground or a soft ground is improved to a firm ground by a simple method, and a non-uniform settlement accident is obviated. The present invention relates to a reinforcing structure for residential ground that can be prevented and a construction method thereof.
[0002]
[Prior art]
In order to support the structure on the ground, a sufficient ground strength is required to support the structure load. In order to achieve this, a pile foundation method has been often used. This construction method is indispensable when constructing heavy structures on soft ground, but its construction field is limited because of high construction costs. Recently, however, the pile foundation method is being adopted in houses for earthquake countermeasures.
[0003]
However, the pile foundation method has the problems that it disturbs the good natural ground that can support the house load, promotes the deformation of the groundwater vein, and affects the surrounding ground. In addition, there is an example where the subsidence of the ground is promoted by the influence disturbed during construction.
[0004]
It is generally well known that there are three factors, (1) moisture content, (2) particle size distribution, and (3) maximum particle size, as important factors for increasing the density of soil in the ground. Moreover, it is also generally performed to ensure uniform quality of the embankment by rolling one layer pressure within 30 cm. However, in order to obtain the maximum dry density of the soil, it is often difficult to adjust the water content in the vicinity of the optimal water content ratio and construct the embankment in a natural environment.
[0005]
Therefore, even if the embankment management according to the method of construction is performed, the density is reduced for some percent of the maximum dry density. This is a major cause of the uneven settlement of houses on the ground.
[0006]
[Problems to be solved by the invention]
In order to bring the soil close to the optimum water content ratio, it is important to add water to the dry soil and drain water from the wet soil. In order to make this adjustment, first, the moisture content test of the embankment material must be performed on site, and the increase / decrease in moisture per unit volume must be calculated. However, when the moisture content test is performed, the moisture content of the soil changes with time.
[0007]
Therefore, if you can roll water while adding water to the ground as a way of thinking and forcibly drain the water below it, you can create the maximum density of the soil. This is a density that does not decrease in volume under any load.
[0008]
Now, it is well-known that soil can yield, and from the yield point, support for the long term and support for the short term are discussed. In some cases, the yield of the soil is a shear failure due to a load action, a structural change of the soil, or a volume change.
[0009]
In any case, these main causes are loads, earthquakes, and water (due to heavy rain). Therefore, if the soil is increased in density, drainage measures are taken, measures against shear failure are taken, and an environment in which the structure does not change is created, it will become solid for a long time.
[0010]
From the above viewpoints, the problem of the present invention is that the soil density of the surface layer part, that is, the created ground or the soft ground part is increased by prescribing the construction method without disturbing the natural ground that can support the house, due to earthquakes, etc. An object of the present invention is to provide a ground reinforcement structure that provides a sufficient function against an unintentional horizontal load and that is a safe ground without affecting the surrounding ground for a long period of time, and a construction method therefor.
[0011]
[Means for Solving the Problems]
The present invention is a structure for reinforcing a residential ground formed on a created ground or a soft ground, and includes a tight layer including a continuous reinforcing material laid on a part or the entire surface of a region to be reinforced, and the top of the tight layer. to the formed by performing rolling compaction, a first compaction layer by soil, and drainage layer composed of a plurality of belt-shaped members laid at a single or spacing laid on the first compaction layer A reinforcing layer composed of a second consolidated layer made of soil, which is formed by rolling water while adding water onto the first consolidated layer including the drainage layer and draining through the drainage layer. It has at least one layer.
[0012]
The tight layer is a layer in which pressure is applied by interposing the continuous reinforcing material between two layers made of a material constituting the tight layer, for example, empty mortar or soil cement.
[0013]
Further, the tightest bottom layer is formed at the boundary between the natural ground and the created ground, the boundary between the hard ground and the soft ground, or the soft ground.
[0014]
Furthermore, the drainage layer is made of various filter materials, for example, a nonwoven fabric or a paper-type filter material, and has a structure capable of draining in the filter direction, and the end portion is extended to reach the outside of the ground.
[0015]
Furthermore, when the lower layer of the lowermost rigid layer is soft, a cracked stone layer in which an aggregate, for example, cracked stone is laid, may be formed on the soft portion.
[0016]
According to this invention, the construction method of the reinforcement structure of the residential ground formed in a creation ground or a soft ground is also provided. This construction method includes a first step of excavating the boundary between the natural ground and the created ground, the boundary between the hard ground and the soft ground, or the soft ground, and a part or the whole of the region to be reinforced at the boundary. A second step of forming a tight layer including a continuous reinforcing material, a third step of forming a first compacted layer of soil on the tight layer, and on the first compacted layer A fourth step of laying a drainage layer composed of one or a plurality of strip-like materials at intervals, and the drainage layer while performing rolling pressure while adding water on the first consolidation layer including the drainage layer A fifth step of forming a second consolidated layer of soil by draining through the first, second, third, fourth, and fifth steps in order, the consolidated layer, the first consolidated layer A reinforcing layer composed of a layer, the drainage layer and the second consolidation layer as one layer, and the second pressure layer in the uppermost layer. Wherein the top surface of the layer to form the reinforcing portion layer upper surface of one or more layers to a level close to the Development Ground.
[0017]
In this construction method, the tight layer is a material constituting the tight layer, for example, a material comprising the continuous reinforcing material after laying an empty mortar or soil cement, and further constituting the tight layer thereon After laying down, it is formed by compacting with a rolling roller or the like so as to obtain an appropriate density.
[0018]
In this construction method, the first consolidation layer is formed by compacting the soil so as to have an appropriate density with a rolling roller after the soil is backfilled.
[0019]
In this construction method, the drainage layer is made of various filter materials, for example, a nonwoven fabric or a paper-type filter material, and has a structure capable of draining in the filter direction, and the end portion extends to the outside of the ground. Thus, the water penetrated into the drainage layer is drained to the outside of the ground by performing compaction with a rolling roller or the like so as to obtain an appropriate density.
[0020]
In this construction method, when the natural ground is soft ground, before forming the bottom solid layer, if necessary, aggregate, for example, split stone or a specific stone, is formed on the soft ground. A bottom layer of a solid layer may be formed on a ground reinforcing material or the like having a length and a thickness.
[0021]
In this construction method, when the boundary between the natural ground and the created ground or the boundary between the hard ground and the soft ground is inclined, stepping may be performed according to the inclination.
[0022]
As is apparent from the above description, the present invention can be said to be a method for forcibly performing the process of the soil returning to the rock.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The ground reinforcing structure according to the present invention is performed on a created ground or a soft ground. In carrying out the present invention, it is necessary to know the boundary between the natural ground and the created ground or the boundary between the hard ground and the soft ground. This boundary is determined by the following method.
[0024]
FIG. 10 is a conceptual diagram of a measurement system for measuring the Rayleigh wave velocity using an exciter in order to know the boundary between the created ground and the natural ground or the boundary between the hard ground and the soft ground when implementing the present invention. It is. The measurement system includes a computing unit 1, a seismometer 2, an excitation signal device 3, an excitation device 4, a first receiver 5, and a second receiver 6. This measurement system generates and amplifies a vibration signal by the vibration signal generator 3, and vibrates the vibration generator 4 in the vertical direction to generate a Rayleigh wave as one of surface waves on the ground surface. If the time during which the Rayleigh wave passes between the first receiver 5 and the second receiver 6 is T, the Rayleigh wave is determined by the time T and the distance S between the first and second receivers 5 and 6. The average speed (for convenience, MVr) can be obtained as MVr = S / T.
[0025]
Further, the Rayleigh wave average velocity can be similarly determined by changing the excitation frequency f, and the Rayleigh wave dispersion characteristic in the depth (depth) direction can be determined. When the depth is H and the wavelength of the Rayleigh wave is λ, H = λ / 2 = MVr / 2 · f. That is, most of the Rayleigh wave travels in a region having a depth of about one wavelength in a semi-infinite elastic body, and the average property in this region is considered to be approximately equal to the property at a depth of ½ wavelength. Because it can.
[0026]
FIG. 11 shows an example of a characteristic curve showing the relationship between the Rayleigh wave average velocity MVr and the depth H obtained by the above measurement system. This characteristic curve shows an example in which the relationship between the Rayleigh wave average velocity MVr and the depth H is measured from the first layer to the fifth layer on the ground composed of a plurality of layers. In this characteristic curve, the depth at which the Rayleigh wave average velocity is first observed is H0 = 0.3 (m), and the Rayleigh wave average velocity MVr0 is 140 (m / sec). And in this characteristic curve, the region up to the depth H1 where the Rayleigh wave average velocity fluctuates greatly according to the depth, and the depth region where the rate of fluctuation of the Rayleigh wave average velocity is almost constant even if the depth changes. There is. The region where the Rayleigh wave average velocity fluctuates greatly as described above is considered to be due to the fact that there is a gap between soil particles and it is not homogeneous. This is a tendency often seen in the so-called created ground layer in which new ground is formed by piling soil from other land on the so-called natural ground.
[0027]
On the other hand, the fact that the rate of fluctuation of the Rayleigh wave average velocity is almost constant means that there is no gap between particles in the soil, which means that it is a natural ground like a clay layer. As a result, the depth of the region where the Rayleigh wave average velocity fluctuates greatly is identified as the depth H1, and this depth H1 (= 1.6m) is the boundary between the created ground and the natural ground below it or the hard ground. It is determined that it is a boundary with soft ground. Such a measurement system is described in detail in Japanese Patent No. 3052224 or Japanese Patent Application No. 2000-183290, and detailed description thereof is omitted here.
[0028]
FIG. 1 is a cross-sectional view showing a reinforcing structure of a residential ground according to the first embodiment of the present invention. In FIG. 1, this reinforcing structure searches for a boundary between natural ground or hard ground (hereinafter abbreviated as natural ground) 10 and constructed ground or soft ground (hereinafter abbreviated as created ground) 20 by the above method. It is formed after excavating to the boundary.
[0029]
The reinforcing structure includes a solid layer 30 including a continuous reinforcing material laid on a part or the entire surface of a region to be reinforced as the ground of the house 100, and a first soil-based layer formed on the solid layer 30. The compaction layer 40 is formed on the first compaction layer 40 including the drainage layer 50 made of a plurality of strip-like materials laid on the first compaction layer 40 or at intervals, and the drainage layer 50. Here, there are two reinforcing layer layers composed of the second consolidation layer 60 made of soil. The lowermost solid layer 30 is formed at the boundary between the natural ground 10 and the created ground 20.
[0030]
As shown in FIG. 2, the reinforcing structure is formed so as to be larger (for example, about 1 m) than the region 101 where the foundation of the house 100 is formed when viewed in plan.
[0031]
Referring to FIG. 3, the lowermost solid layer 30 is a layer to which pressure is applied by interposing a continuous reinforcing material 33 between two layers 31, 32 made of, for example, empty mortar or soil cement. The pressure is applied using, for example, a device called a vibration roller. The vibration roller is a roller that has a weight of about several hundred kilograms and that travels while applying vibrations to roll the rolling force so as to obtain an appropriate density. As a result of such rolling, the dense layer 30 bites into the natural ground 10. FIG. 3 shows that the position indicated by the alternate long and short dash line is the original boundary between the natural ground 10 and the created ground 20.
[0032]
As is well known, the empty mortar is a mortar to which water of about 1: 3 mortar is not added. Soil cement is also well known. In any case, empty mortar or soil cement is spread to a thickness where water is not added, and continuous reinforcing material 33 is laid on the mortar or soil cement to a certain thickness. In addition, when the above rolling is performed, a very hard layer is formed.
[0033]
The continuous reinforcing member 33 is a material having a tensile strength with a prescribed strength (for example, 20 kN / m or more), such as carbon fiber, glass fiber, aramid fiber, polyvinyl alcohol fiber, and polyacetal fiber. Some materials are formed into mesh plates. Some of these are already on the market. However, commercially available continuous reinforcing materials are often provided in the form of rolls having a certain width. In this case, as shown in FIG. 4, when the pulling force acting on the ground is only in two directions as indicated by the arrows, the continuous reinforcing material is partially or entirely on the region to be reinforced described in FIG. What is necessary is just to construct | lay, 33 partially overlapping. However, usually, the tensile force acting on the ground is not limited to two directions. In this case, the overlap portion of the continuous reinforcing material 33 is welded on site. Of course, after making it in the shape shown in FIG. 4 in another place, you may make it carry in to the spot.
[0034]
Returning to FIG. 1, the first compacted layer 40 is to backfill the excavated soil on the compacted layer 30 formed as described above, and roll this with the vibrating roller or the like. It is a layer hardened so as to have an appropriate density.
[0035]
FIG. 5 shows a cross-sectional structure of the drainage layer 50. As shown in FIG. 5A, the drainage layer 50 is made of a filter material 51 such as a nonwoven fabric or paper, and usually has a drainage thin tube 52 in the length direction thereof. However, as shown in FIG. 5 (b), some fibrous materials are intricately entangled and do not have capillaries. Some of such drainage layers are already on the market. This kind of drainage layer is also often provided in the form of a roll having a certain width. Therefore, as shown in FIG. 6, when a plurality of drainage layers 50 are laid, the drainage layers 50 are laid at a certain interval L on the first consolidation layer 40 formed as described above. In particular, as shown in FIG. 1, the end of the drainage layer 50 is extended so as to reach the outside of the creation ground 20. This is because the moisture that exudes in the soil by rolling pressure is absorbed when the second consolidated layer 60 described below is formed, and the absorbed moisture is discharged onto the formation ground 20 by the capillary phenomenon by the thin tubes 52 and the like. is there. For this reason, a water receptacle such as a bucket is placed at the end of the drainage layer 50 to receive the discharged water. In addition, as for the edge part of this drainage layer 50, when construction of a reinforcement structure is complete | finished, the part which has come out from the creation ground 20 will be cut | disconnected, or it will be embedded in the soil.
[0036]
In this embodiment, another reinforcing portion layer is formed on the reinforcing portion layer formed as described above. This second reinforcing portion layer is also formed by the same method as described above. That is, on the second consolidated layer 60 of the first reinforcing part layer, the second layered reinforcing part layer 30 'is formed, and subsequently, the first consolidated layer 40' is formed. A drainage layer 50 'is laid on the first consolidated layer 40', and a second consolidated layer 60 'is further formed. The upper surface of the second consolidated layer 60 ′ is set to a level near the upper surface of the creation ground 20.
[0037]
FIG. 7 shows a cross-sectional structure of a tight layer formed at the boundary between the nth layer and the (n + 1) th layer when the reinforcing portion layer is formed as an (n + 1) layer (n is a positive integer). This tight layer is also the same as the tight layer 30 in FIG. 3 in that it is formed by applying pressure with a continuous reinforcing material 33 interposed between two layers of, for example, empty mortar or soil cement. is there.
[0038]
The foundation (fabric foundation, solid foundation, etc.) 110 of the house 100 is formed on the second consolidated layer 60 'of the second reinforcing portion layer formed as described above.
[0039]
FIG. 8 is a cross-sectional view showing a second embodiment of the reinforcing structure according to the present invention. This embodiment is applied when the natural ground 10 is a soft ground. In this case, before the lowermost solid layer 30 is formed, a chestnut stone layer 70 in which an aggregate, for example, a split stone is laid on the natural ground 10 is formed. Ensure that the walnut stone is fully acclimated to the natural ground. In place of aggregate, a ground reinforcement material having a specific length and thickness, for example, a chemical fiber or resin material having a length of about several tens of cm to 2 m that serves as a bamboo root in bamboo bamboo. A reinforcing material may be used. The method for forming the first and second reinforcing layer is the same as in the first embodiment.
[0040]
FIG. 9 is a cross-sectional view showing a third embodiment of the reinforcing structure according to the present invention. This embodiment is applied when the boundary between the natural ground 10 and the created ground 20 is inclined as indicated by a one-dot chain line. In this case, the step is cut according to the inclination. Here, the case where a reinforcement structure is constructed on a slope is demonstrated. First, the construction part of the reinforcement structure on the slope is excavated. Then, a crushed stone or concrete foundation 80 is formed on the lower side of the inclined boundary, and a concrete wall 90 for earth retaining is formed on the crushed stone or concrete foundation 80. Subsequently, the first reinforcing portion layer is formed in a stepped state, and the second reinforcing portion layer is formed thereon. The first and second reinforcing layer layers are formed in the same manner as in the first embodiment, but the end portions of the drainage layers 50 and 50 'are not extended, and the end portions of the concrete wall 90 are not extended. A draining pipe 91 is embedded in the corresponding portion in advance.
[0041]
In addition, also when building a house on a turret-shaped ground, the form of FIG. 9 without a step can be applied. That is, after the periphery is surrounded by a concrete wall, the inside of the concrete wall is excavated, and a plurality of reinforcing portion layers are formed there.
[0042]
Below, the construction method of a reinforcement structure is demonstrated. First, the layer boundary between natural ground or hard ground and developed ground or soft ground is examined by the ground survey described above. Then, excavation is performed to the measured layer boundary, and, for example, empty mortar is sprinkled to a predetermined thickness at the layer boundary, and then, for example, continuous reinforcing material is laid. As described above, when the layer boundary is inclined, the continuous reinforcing material is laid after stepping. While adding empty kneading mortar on the continuous reinforcing material, rolling is repeated 6 to 8 times with a vibrating roller. This forms a tight layer.
[0043]
Next, about 30 cm of soil is backfilled in the upper part, and the rolling is repeated for 8 or more runs while applying vibration with the vibration roller. Thus, the first consolidation layer is formed. A drainage layer is laid on this upper surface. No empty mortar is added to this surface. Furthermore, about 30 cm of soil is refilled in the upper part, and rolling is repeated while applying vibration with a vibration roller. Thus, the first reinforcing portion layer is formed.
[0044]
Subsequently, empty mortar is spread to a predetermined thickness, and a continuous reinforcing material is laid. Further, rolling is repeated 8 times with the vibrating roller while adding the empty mortar. Next, about 30 cm of soil is backfilled in the upper part, and the rolling is repeated for 8 or more runs while applying vibration with the vibration roller. A drainage layer is laid on this upper surface. Also, no empty mortar is added to this surface. Furthermore, about 30 cm of soil is refilled in the upper part, and rolling is repeated while applying vibration with a vibration roller. Thus, the second reinforcing portion layer is formed.
[0045]
By repeating the above construction, a shear resistance layer is formed at the layer boundary between natural ground or hard ground and created ground or soft ground, and a similar shear resistance layer is formed on the upper 60 cm, sandwiched between the intermediate portions. Therefore, a drainage layer can be formed.
[0046]
【The invention's effect】
According to the present invention described above, the natural ground that can support the house is not disturbed, and the soil density of the surface layer part, that is, the created ground or the soft ground part is increased by prescribing the construction method. Therefore, it is possible to provide a reinforcing structure that exhibits a sufficient function and can be a safe ground without affecting the surrounding ground for a long time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining a reinforcing structure of a residential ground according to a first embodiment of the present invention.
2 is a plan view for explaining a formation region of a lowermost rigid layer with respect to the foundation of the house in FIG. 1. FIG.
3 is a cross-sectional view for explaining the structure of the lowermost rigid layer in the reinforcing structure in FIG. 1. FIG.
4 is a plan view for explaining a method when a continuous reinforcing material is laid on the tight layer of FIG. 2; FIG.
FIG. 5 is a partial cross-sectional view for explaining the structure of the drainage layer in FIG. 1;
6 is a plan view for explaining a drainage layer laying method in FIG. 1; FIG.
FIG. 7 is a cross-sectional view for explaining the structure of an intermediate layer of the reinforcing structure in FIG. 1;
FIG. 8 is a cross-sectional view for explaining a reinforcing structure for a residential ground according to a second embodiment of the present invention.
FIG. 9 is a cross-sectional view for explaining a reinforcing structure of a residential ground according to a third embodiment of the present invention.
FIG. 10 is a block diagram showing a configuration of a measurement system used to measure the boundary between natural ground and created ground when implementing the present invention.
FIG. 11 is a diagram showing an example of a characteristic diagram used for determining the boundary between the natural ground and the created ground using the data measured by the measurement system of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Natural ground or hard ground 20 Formation ground or soft ground 30, 30 'Solid layer 40, 40' 1st compaction layer 50, 50 'Drainage layer 60, 60' 2nd compaction layer 70 Kuriishi layer 80 Concrete foundation 90 Concrete wall 100 housing 101 housing foundation

Claims (11)

In the reinforcing structure of the residential ground formed on the created ground or soft ground,
A solid layer including a continuous reinforcing material laid on a part or the entire surface of the region to be reinforced, and a first consolidated layer formed of soil by rolling on the solid layer; One drainage layer laid on the first consolidation layer or a plurality of strip-like material laid at intervals, and rolling while applying water to the first consolidation layer including the drainage layer A structure for reinforcing a residential ground, comprising at least one reinforcing part layer formed by draining through the drainage layer and formed of a second consolidated layer of soil.   2. The housing according to claim 1, wherein the tight layer is a layer in which pressure is applied with the continuous reinforcing material interposed between two layers made of a material constituting the tight layer. Ground reinforcement structure.   The reinforcing structure according to claim 1 or 2, wherein the tightest layer in the lowermost layer is formed at the boundary between the natural ground and the created ground, at the boundary between the hard ground and the soft ground, or in the soft ground. Reinforcement structure of residential ground.   The reinforcing structure according to any one of claims 1 to 3, wherein the drainage layer is made of various filter materials and has a structure capable of draining in the direction of the filter, and the end portion is extended to reach the outside of the ground. Reinforcement structure for residential ground, characterized by   5. The reinforcing structure for a residential ground according to claim 4, wherein when the lower side of the tightest layer of the lowermost layer is soft, aggregate is introduced. In the construction method of the reinforcing structure of the residential ground formed on the created ground or soft ground,
A first step of excavating the boundary between the natural ground and the created ground or the boundary between the hard ground and the soft ground, or into the soft ground;
A second step of forming a tight layer including a continuous reinforcing material on a part or the entire surface of the boundary and the region to be reinforced;
A third step of forming a first compacted layer of soil on the compacted layer;
A fourth step of laying a drainage layer made of a plurality of strip-like materials at one or intervals on the first consolidation layer;
A fifth step of forming a second compacted layer of soil by rolling on the first consolidated layer including the drained layer while performing water compaction while draining through the drained layer . , 2nd, 3rd, 4th, 5th ,
The reinforcing layer composed of the tight layer, the first consolidated layer, the drainage layer, and the second consolidated layer is used as one layer, and the upper surface of the uppermost second consolidated layer is the upper surface of the creation ground. A method for constructing a reinforcing structure for a residential ground, wherein one or more of the reinforcing portion layers are formed until a level close to that of the housing is obtained.   The construction method according to claim 6, wherein the tight layer is appropriately formed after laying the continuous reinforcing material after laying the material constituting the tight layer and further laying the material constituting the tight layer thereon. A method for constructing a reinforcing structure for residential ground, characterized in that it is formed by compacting so as to obtain a high density. 8. The construction method according to claim 6 or 7, wherein the first consolidation layer is formed by compacting so as to have an appropriate density after the soil is backfilled. Method of reinforcing structure.   The construction method according to claim 8, wherein the drainage layer is made of a paper-based filter material and has a structure capable of draining in the filter direction, and the end is extended to reach the outside of the ground. A method for constructing a residential ground reinforcing structure, characterized in that the water penetrated into the drainage layer is drained to the outside of the ground by performing compaction to an appropriate density.   In the construction method according to any one of claims 6 to 9, when the natural ground is soft ground, before forming the lowermost solid layer, if necessary, bone is attached to the soft ground. A method for constructing a reinforcing structure for a residential ground, characterized in that a ground reinforcing material or the like having a specific length and thickness is laid and solidified, and a solid layer at the bottom layer is formed.   In the construction method in any one of Claims 6-10, when the boundary of the said natural ground and the said creation ground or the boundary of a hard ground and a soft ground is inclined, a leveling is carried out according to inclination. The construction method of the reinforcement structure of the ground for housing characterized by performing.

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