JP5203872B2 - Excess liquid recycling method in soil cement body construction method - Google Patents

Description

  The present invention relates to a surplus liquid recycling method in a soil cement body construction method applied to a mountain retaining wall method or a ground improvement method for constructing a soil cement body such as a soil cement wall or a soil cement column.

  The mountain retaining wall method and the ground improvement method are methods of mixing soil in place and cement milk to construct soil cement walls, etc. in the ground. With the increase in construction results, surplus mud soil that is industrial waste The amount of waste disposal has also increased dramatically.

  The surplus liquid recycling method classifies and recovers cement-based suspensions from surplus mud generated during the construction of soil cement walls, etc., and reuses them as an infusion solution. The amount of disposal is greatly reduced, and the use material such as cement is reduced (see, for example, Patent Documents 1, 2, 3, and 4).

FIG. 3 is a schematic diagram of such a surplus liquid recycling method, and FIG. 4 is a flowchart comparing the conventional method and the recycling method. In FIG. 3, surplus mud 1 generated in connection with the construction of the soil cement columnar continuous wall is sent to a soil separator 11 composed of a vibrating sieve and a liquid cyclone by a soil vacuum wheel 10 to collect surplus cement milk recovered liquid 2 and Sediment (also referred to as waste soil, industrial waste mud soil, industrial waste disposal soil) 3 is separated into 3 and added to the recovered liquid 2 of the surplus cement milk collected at the plant 12 and used as a recycle mixed liquid 5 by adding a new cement milk additional liquid 4 To do.

  In such a recycling method, conventionally, the number of times of recycling is not limited, and a method of adding and adjusting the recovered recovered cement milk recovered liquid and using it as much as possible has been adopted. Moreover, the property of the soil cement in each process to be recycled was determined only by the specific gravity measurement result of the recovered liquid.

Japanese Patent Application Laid-Open No. 07-1439 JP 2001-271338 A JP 2002-54139 A JP 2004-169302 A

  In the case of the conventional recycling method described above, the recovered excess cement milk recovered liquid is added and repeatedly used, so the amount of fine particles contained in the recycled mixed liquid increases with the number of recycling. Increasing and adversely affecting the quality of soil cement walls.

  In addition, because the properties of soil cement at each stage of the recycling process cannot be accurately grasped, it was judged only from the specific gravity measurement result of the recovered liquid and adjusted until the target specific gravity was reached with new cement milk. Was not enough.

  The present invention has been made in view of such circumstances, and a soil cement wall that is constructed by recycling construction by using the recycling construction method used in the soil cement body construction construction method and adding improvements to the construction method. It is an object of the present invention to provide a surplus liquid recycling method in the soil cement body construction method that can make the quality of the soil cement constant and can construct a good soil cement wall and the like.

Claim 1 of the present invention collects surplus mud soil discharged in the soil cement body construction method in which the soil cement body is constructed in the ground by mixing and stirring the current position soil and cement milk, and industrial waste is recovered from the recovered surplus mud soil. Separation of mud soil and surplus cement milk containing fine-grained soil that becomes residual sediment, and add new cement milk to the recovered liquid of the surplus cement milk. in the liquid recycle method, with respect to 1 construction unit set in advance, and starts the construction in basic formulation solution of cement milk, limit the recycled number from recycling liquid combination a plurality of times for each construction unit, recycling operations Use the program to determine the sediment content of the recovered liquid and add new cement to the recovered liquid to be added to the recovered liquid according to the residual sediment content in the recovered liquid. This is a surplus liquid recycling method in a soil cement body construction method characterized by constructing a soil cement body of uniform quality in the depth direction by determining the additional amount of milk and completing the recycling.

  That is, in the recycling method of the present invention, the recovered surplus soil cement is limited to each preset construction unit, and recycling is performed, and each constant necessary for construction is calculated using the recycling calculation program. It is intended to construct soil cement walls with a certain quality. More specifically, it has the following improvements.

(1) Setting standard composition by soil (see Table 1)
a) Because the recycling method is the key to separating and recovering excess mud soil, considering the fine grain content of the soil classification as an important element of the soil evaluation scale, 5 types of soil classification based on the unified Japan soil classification The standard composition of the recycling method is set according to the above five soil classifications.

      b) The standard composition is the same as the water cement ratio (W / C) of the standard composition of the general soil method, and the quality (uniaxial compressive strength) of the mud in the drilling hole is maintained.

      c) The amount of the setting retarder used is reduced compared to the conventional case because the residence time of the recovered liquid is greatly shortened.

(2) Extra injection rate (see Table 1)
a) Due to the characteristics of the recycling method, it is necessary to keep the fluidity of the mud higher than that of the general soil method, and it is also necessary to prevent the deterioration of quality due to the sand contained in the recovered liquid.

      b) For this reason, in this recycling method, it is preferable to increase the cement milk injection rate by 1.2 to 1.3 times, for example, according to the soil quality, according to the soil quality, according to the soil quality (the fine soil content rate is an evaluation scale).

      c) As a result, the agitation and kneading conditions of cement milk and local soil are improved as compared with the general soil method, high quality mud is generated, and compressive strength and water stoppage are increased.

(3) Do not add water to the recovered liquid a) Cement milk components are usually included in the recovered liquid at 60 to 80%. If diluted water is added to this recovered liquid, the original water cement ratio (W / C) May change, leading to a decrease in strength of the mud in the drilling hole.

      b) Therefore, without adding water to the excess mud or the recovered liquid in principle, the cement milk properties in the recovered liquid are utilized as they are.

      c) It should be noted that the minimum required amount of cleaning water such as cone cleaning water and soil separator is acceptable, and the cement milk injection rate is increased in consideration of the amount of diluted water.

(4) Limit on the number of recycling (see Fig. 1 and Fig. 2)
a) If water is added to the recovered liquid without limitation, it can be performed any number of times, but the workability is deteriorated and the quality of the mud in the drilling hole may be degraded, so the number of recycling is limited to a plurality of times.

      b) The number of recycling is preferably 2 times. The number of times of recycling can be determined by comprehensively considering the quality maintenance of the mud in the drilling hole, the construction time, the industrial waste mud reduction rate, and the like.

      c) The construction with the set number of recyclings means that the construction unit such as the soil cement wall is set, and the usage ratio of the basic blended liquid and the recycled blended liquid is determined.

d) The new cement milk usage rate, that is, the new cement milk addition amount of the additional liquid mixture added to the recovered liquid can be calculated by using a recycling calculation program for obtaining the sediment content rate and the industrial waste mud reduction rate of the recovered liquid. .

(5) Setting of one construction unit a) In the present invention, one construction unit starts drilling with the basic blending solution, and completes the soil cement wall and the like with the recycled blending solution in which the additional blending solution is added to the collected recovered solution. It is a “unit” to be made.

      b) An example of one construction unit is shown below (claim 2).

1 element (leading / following / continuous)
Leading element + trailing element
1/2 element (large caliber and large depth)
c) The method of determining one construction unit is determined in consideration of the following factors.

Recycle tank capacity> Amount of liquid collected by basic formulation generated per unit of construction
Amount of recycled liquid used in one unit of construction> Amount of finished batch in a plant d) Therefore, in one unit of construction, drilling must be started from new cement milk, and drilling should be completed with recycled liquid. It leads to quality maintenance and improvement of workability in the borehole mud.

(6) Properties and amount of additional liquid mixture a) The additional liquid mixture is new cement milk added to the recovered liquid to make up for the shortage of cement in the recovered liquid.

b) The recovered liquid contains cement milk components and fine-grained soil (sediment) . If this fine grain soil content rate (sediment content rate) becomes high and it uses as it is as a recycle liquid, it will cause the quality fall of mud in a drilling hole.

      c) Therefore, it is necessary to add cement milk according to the amount of earth and sand in the recovered liquid, and this blending and amount are determined.

      d) The properties of the additional blending liquid are the properties obtained by removing bentonite from the basic blending, and the water cement ratio (W / C) is set to be the same.

      e) The additional amount shall be the amount of residual sediment in the recovered liquid multiplied by the cement milk injection rate.

      f) As a result, the properties of the recycled liquid mixture are almost the same as the new cement milk.

(7) Properties of the recycle liquid mixture a) The recycle liquid mixture is a mixture of the recovered liquid and the above additional liquid mixture.

      b) The properties (W / C) and injection rate of cement milk are the same as the new cement milk.

      c) Basically, the remaining amount of the recovered liquid used for the recycled liquid becomes zero after the end of one construction unit.

      d) Observe the amount of recycled liquid used throughout the plant data and manage whether the planned reduction rate has been achieved.

(8) Recycle calculation program (see Table 2)
a) lapis lazuli cycle calculation program used in the present invention, for each soil type of the target ground, fine fraction content of the target ground, as a wet unit weight, the water content ratio, etc. parameters, the excess soil cement incidence, recovery, Each constant required for construction is calculated by a calculation program that takes into consideration the sediment content, the fine coarse particle composition rate, etc. of the recovered liquid (Claim 3).

      b) Input and setting items are the soil conditions (soil particle specific gravity, fine soil content, wet unit volume weight, surplus rate), construction conditions (coarse soil discharge rate, fine soil discharge rate, cement milk) Emission rate, surplus mud suction rate, injection rate increase rate), basic composition of general construction method (cement milk injection rate, unit volume weight, water cement ratio, etc.).

      c) Calculation items are basic formulation (cement milk injection rate, unit volume weight, water cement ratio, etc.), additional formulation (cement milk unit volume weight, water cement ratio, etc.), basic formulation usage rate, additional formulation addition rate The unit volume weight of the excess mud, the unit volume weight of the recovered liquid, the sediment content of the recovered liquid, the recovery rate, the additional blending rate, the industrial waste mud generation rate, the industrial waste mud reduction rate, etc.

  Based on the data calculated as described above, for each construction unit, the construction starts with the basic composition of cement milk, and the amount of each new cement milk added in the multiple recycling is determined. Implement secondary and secondary recycling work to complete recycling. In addition, construction management is performed using the calculated data.

  (1) Start the construction with the basic compound solution, and perform the recycle limited to each preset construction unit for the recovered surplus cement, and use the recycling calculation program for one construction unit. By determining the amount of new cement milk to be added to the recovered liquid and completing the recycling, the quality of the soil cement wall to be built can be made constant, and a good soil cement wall, etc. will be built. be able to.

  (2) Since the recycling method used in the soil cement ground improvement method is used and only improvements need to be made, a low cost recycling method can be realized.

  (3) The recycling calculation program makes it easy to check the operating status of the recycling system by checking the control points (specific gravity and flow value) at each construction stage, and if it deviates from the expected value, it is easy to identify and correct the cause. Can be done.

  Hereinafter, the present invention will be described based on the illustrated embodiments. This embodiment is an example applied to the construction of a soil cement column row continuous wall. FIG. 1 is a conceptual diagram showing an example of a surplus liquid recycling method in the soil cement body construction method of the present invention. FIG. 2 is a conceptual diagram showing an example of one construction unit in the present invention.

First, in this recycling method, separation and recovery of surplus mud soil is the key. Therefore, considering the fine grain content of the soil classification as an important element of the soil evaluation scale, as shown in Table 1, it is standardized in Japan. based on soil classification, the soil classification classified into five types, quantity and water-cement ratio cement milk injection volume of cement weight bentonite volume and water of a standard formulation i.e. target earth 1.0m per ³ cement milk each soil segment, etc. Set.

  In Table 1, the standard composition is the same as the water cement ratio (W / C) of the standard composition of the general soil method, and retains the quality (uniaxial compressive strength) of the mud in the borehole. The setting retarder was reduced compared to the conventional method because the residence time of the recovered liquid was significantly shortened. In addition, the fluidity of the mud must be kept higher than that of the general soil method, and it is necessary to prevent quality degradation due to the sand contained in the recovered liquid. The cement milk injection rate is 1.2 to 1.3 times higher than the general soil method depending on the soil quality. As a result, the agitation and kneading conditions of cement milk and local soil are improved as compared with the general soil method, high quality mud is generated, and compressive strength and water stoppage are increased.

In the recycling method of the present invention, as shown in FIG. 1 and FIG. 2, construction is started with the basic blended liquid of cement milk determined using Table 1 for one construction unit, and the recycling by the recycled blended liquid is performed. the number is limited to several times, for each construction unit, with a recycling operation program, to determine the new cement milk additional amount of additional mixing liquid added to the recovering solution, by completing the recycling, in the depth direction Build a soil cement body of uniform quality.

  The embodiment of FIGS. 1 and 2 is a case where one element is one construction unit, one element is divided into three in the depth direction, and the number of recycling is limited to two. Recycling is carried out according to the following procedure.

(1) Initial construction The upper target soil is excavated and stirred with the basic composition liquid of cement milk, and the generated surplus mud 1-1 is separated into the surplus cement milk recovery liquid 2-1 and the earth and sand 3-1. The recovered liquid 2-1 consists of cement milk and earth and sand, and a new cement milk additional liquid mixture 4-1 corresponding to the residual earth and sand content is added to the recovered liquid 2-1, and the primary recycle liquid mixture 5-1 and To do. The properties of the recycle composition liquid 5-1 are almost the same as the new cement milk.

(2) Primary recycling construction The target soil in the middle part is excavated and stirred with the primary recycling mixture 5-1, and the generated excess mud 1-2 is separated into the excess cement milk recovery liquid 2-2 and earth and sand 3-2. To do. To the recovered liquid 2-2, a new cement milk addition liquid 4-2 corresponding to the residual sediment is added to obtain a secondary recycling liquid mixture 5-2. The properties of the recycle composition liquid 5-2 are almost the same as the new cement milk.

(3) Secondary recycling construction The lower target soil is excavated and stirred with the secondary recycling liquid 5-2, and one unit of construction is completed using the generated excess mud 1-3 as the disposal mud. At the end of one construction unit, the remaining amount of the recycle recovery liquid is zero and the recycle recovery liquid is used up.

Add blended liquid new cement milk added amount of the added to the recovering solution were calculated using the recycling operation program and performs a construction management using the calculated data. Table 2 shows an example of input / setting items, formulation / calculation items, and calculation / calculation results of this calculation program.

  The input and setting items are the soil condition (soil particle specific gravity, fine soil content, wet unit volume weight, surplus rate), construction conditions (coarse soil discharge rate, fine soil discharge rate, cement milk discharge rate) -Excess mud soil suction rate / injection rate increase rate), basic composition of general construction method (cement milk injection rate, unit volume weight, water cement ratio, etc.).

  Calculation items are basic formulation (cement milk injection rate / unit volume weight / water cement ratio, etc.), additional formulation (cement milk unit volume weight / water cement ratio, etc.), basic formulation solution usage rate, additional formulation solution addition rate, surplus Unit volume weight of mud, unit volume weight of recovered liquid, sediment content rate of recovered liquid, recovery rate, additional blending rate, industrial waste mud generation rate, industrial waste mud reduction rate, etc.

  Based on the calculated data in Table 2, construction starts with the basic composition of cement milk for one construction unit, and the amount of each new cement milk added in the second recycling is determined. Implement the following recycling work to complete the recycling. In addition, construction management is performed using the calculated data.

  Needless to say, the present invention is not limited to the above embodiment.

It is a conceptual diagram which shows an example of the surplus liquid recycling construction method in the soil cement body construction construction method of this invention. It is a conceptual diagram which shows an example of 1 construction unit in this invention. It is a schematic diagram of a surplus liquid recycling construction method. It is the flowchart which compared the conventional construction method and the recycling construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Surplus mud 2 ... Recovery liquid 3 ... Earth and sand 4 ... Additional compounding liquid 5 ... Recycle compounding liquid 10 ... Soil vacuum car 11 ... Soil separator 12 ... Plant

Claims (3)

The surplus mud discharged in the soil cement body construction method that mixes and agitates the current position soil and cement milk and constructs the soil cement body in the ground is recovered, and the soil and residual soil and sand that become industrial waste mud from the recovered surplus mud In the surplus liquid recycling method that separates the surplus cement milk containing fine-grained soil to be used, and adds the additional blended liquid of new cement milk to the recovered liquid of the surplus cement milk to be used as a recycle blended liquid for one construction unit, starts the construction in basic formulation solution of cement milk, limit the recycled number from recycling liquid combination a plurality of times for each construction unit, sediment recovered liquid using a recycling operation program the partial content determined, determine the new cement milk additional amount of additional mixing liquid added to the recovering solution in response to the residual sediment content in the recovered solution , By to complete the recycling, excess liquid recycling method in soil cement body reclamation method characterized by constructing a soil cement having a uniform quality in the depth direction.   The surplus liquid recycling method according to claim 1, wherein one construction unit is one element of a cement cement body, a preceding element and a trailing element, or a 1/2 element. Liquid recycling method. In the surplus liquid recycling method according to claim 1 or claim 2, the input / setting items of the recycling calculation program are the basic composition of soil conditions, construction conditions and general construction method of the target ground, and mainly the basic composition and additional composition Surplus liquid recycling method in soil cement body construction method, characterized by calculating the recovery rate, sediment content rate of recovered liquid, industrial waste mud generation rate, industrial waste mud reduction rate.

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