Method for controlling deformation of building structure by combined use of grouting and isolation wall

Abstract

The application discloses a method for controlling deformation of a building by jointly using grouting and a partition wall, and comprises the following steps: obtaining the position and quantity of grouting holes, the range of the grouting expansion area in the grouting hole and the position and burial depth of the partition wall by theoretical calculation or numerical simulation; accurately setting the grouting pipe, each grouting pipe being composed of an A pipe and a B pipe which are bound together, the area between the bottom wall of the B pipe and the bottom wall of the A pipe being the grouting expansion area; grooving the ground at the preset position of the partition wall, and then pouring the partition wall in the groove; drilling the grouting hole by using a drilling machine according to the set position; excavating a foundation pit on the inner side of the partition wall, and measuring the horizontal deformation of the building to be rectified by using an instrument in sections; when the horizontal deformation exceeds the set alarm value, inserting the grouting pipe into the grouting hole at the position corresponding to the horizontal deformation according to the horizontal deformation measurement result to perform grouting. The method can effectively increase the control effect on the building to be rectified and reduce the deformation of other buildings.

Description

Technical Field

[0001] This invention relates to underground engineering construction methods, specifically to methods for controlling the deformation of tunnels and other structures during construction. Background Technology

[0002] Taking the process of foundation pit excavation as an example, the unloading effect of the soil will cause deformation of the foundation pit retaining structure, resulting in displacement deformation of adjacent buildings and structures. For subway tunnels, when the tunnel is located on the side of the foundation pit, the unloading of the soil excavation inside the pit will cause the tunnel outside the pit to bulge. At the same time, the lateral deformation of the foundation pit retaining structure will cause the loss of soil at the bottom of the tunnel, which will then lead to tunnel subsidence. These deformations will cause large deformations in the subway shield tunnel or station structure, and may even cause serious problems such as segment cracking, wall cracking, and water leakage.

[0003] Taking subway tunnels as an example, necessary control measures are often required to reduce the impact of foundation pit construction on adjacent existing tunnels. Existing deformation control measures are divided into passive control measures and active control measures. Among them, passive control measures are beneficial to reduce tunnel deformation, but engineering practice shows that passive measures are generally determined in advance before foundation pit excavation. During the foundation pit excavation process, it is generally impossible to actively and timely control tunnel deformation, and it usually leads to a significant increase in foundation pit cost and a significant increase in construction period. In addition, a single passive measure is difficult to achieve millimeter-level deformation control of adjacent operating tunnels.

[0004] Grouting is an important and common active deformation control measure in construction. Currently, there is considerable research on grouting to lift existing buildings or tunnels, but less research on grouting to control horizontal tunnel deformation; a systematic grouting strategy for controlling horizontal tunnel deformation is still lacking. In actual construction, when the deformation of the structure to be controlled is large, the effect of grouting in controlling tunnel deformation can be enhanced by increasing the grouting volume or using multiple rows of grouting holes. However, this also poses a greater threat to nearby buildings or foundation pit support structures. As a passive control measure, existing research has not yet addressed the effectiveness of combining grouting and isolation walls in controlling tunnel deformation. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a method for controlling the deformation of buildings and structures by combining isolation walls and grouting. This method can increase the effectiveness of deformation control and effectively reduce the adverse effects on the other side of the area to be corrected, achieving high efficiency and economy in deformation control.

[0006] To solve the above technical problems, the following technical solution is adopted.

[0007] The present invention discloses a method for controlling the deformation of buildings and structures by combining grouting and isolation walls, comprising the following steps:

[0008] Step 1: Before excavating the foundation pit or during the excavation process, obtain the location and number of grouting holes between the foundation pit and the building to be corrected, the range of the grouting expansion zone at the bottom of the grouting holes, and the location and depth of the isolation wall between the foundation pit and the grouting holes through theoretical calculation or numerical simulation.

[0009] Step 2: Prepare grouting pipes. Each grouting pipe consists of pipe A and pipe B tied together. The axes of pipe A and pipe B are parallel and their top surfaces are flush. The length of pipe B is greater than the length of pipe A. The area between the bottom wall of pipe B and the bottom wall of pipe A is the grouting expansion area.

[0010] Step 3: Cut a groove in the ground at the preset location of the isolation wall, and then pour the isolation wall in the groove. The isolation wall is arranged parallel to the building structure. The distance between the outer wall of the isolation wall on the side closer to the building structure and the center line of the grouting hole is 1 to 2 meters. The isolation wall is a cement-soil mixing wall.

[0011] Step 4: Drill grouting holes at the designated locations using a drilling machine, and use mud slurry to protect the drilling walls.

[0012] Step 5: Excavate the foundation pit inside the isolation wall. Simultaneously, based on the measuring points placed on the structure to be corrected, measure the horizontal deformation of the structure in sections using instruments. When the horizontal deformation exceeds the alarm value set before the foundation pit construction, insert grouting pipes into the grouting holes at the corresponding positions of the horizontal deformation, and perform the following grouting process to reduce the horizontal deformation of the structure to be corrected to below the alarm value:

[0013] The first step is to inject cement grout through pipe B until cement grout flows out of the grouting hole, ensuring that the entire grouting hole is filled with cement grout.

[0014] The second step is to inject water glass through pipe A, so that the cement slurry and water glass are mixed within the length of pipe A below the surface of the grouting hole, and the hole is sealed.

[0015] The third step is to inject a dual-liquid grout through pipe B to control soil deformation. The dual-liquid grout is made by uniformly mixing cement grout and water glass.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] 1. The present invention combines the use of isolation walls and grouting to improve the control effect on the object to be corrected. This is because the rigidity of the isolation wall is greater than that of the soil, and the isolation wall has a reaction force effect on the grouting, which can increase the control effect on the building to be corrected. At the same time, it has a shielding effect, which can reduce the deformation of other surrounding buildings and structures.

[0018] 2. Compared with the measures of using grouting or isolation walls alone to achieve the same state for the object to be corrected, the present invention can use a smaller total amount of grout, which is economical and environmentally friendly.

[0019] 3. In deformation control measures, grouting alone will cause deformation of the structure on the other side of the object to be corrected, and isolation walls alone cannot actively restore the existing deformation. However, the combined use of grouting and isolation walls can reduce the deformation of the other side, such as the foundation pit retaining structure or other buildings, and increase the deformation effect of the object to be corrected. Compared with using a single measure, its control efficiency is higher. Attached Figure Description

[0020] Figure 1 Cross-sectional layout diagram for combined use of grouting and isolation wall;

[0021] Figure 2 Plan layout for combined use of single-row grouting and isolation wall;

[0022] Figure 3 Plan layout for combined use of multi-row grouting and isolation walls;

[0023] Figure 4 This is a schematic diagram of the grouting pipe layout;

[0024] Figure 5 A comparison diagram showing the horizontal displacement of adjacent soil or isolation wall caused by grouting with and without an isolation wall; Detailed Implementation

[0025] To make the objectives, solutions, and advantages of the present invention clearer, the present invention will be further described below with reference to the accompanying drawings and a specific embodiment.

[0026] The design concept of this invention is to utilize the reaction force effect and shielding effect of the isolation wall, and based on the deformation of the object to be corrected and the location of other nearby buildings and structures, combined with the results of theoretical calculations and numerical simulations, determine the location and number of grouting holes, as well as the location of the isolation wall, in order to increase the control effect on the object to be corrected and reduce the impact on other nearby structures.

[0027] As shown in the attached figure, a method for controlling the deformation of a building structure by combining grouting and a partition wall according to the present invention includes the following steps:

[0028] Step 1: Before or during the excavation of the foundation pit, calculate the location and number of grouting holes between the foundation pit 4 and the structure 1 to be corrected, the extent of the grouting expansion zone 2 at the lower part of the grouting holes, and the location and depth of the isolation wall 3 between the foundation pit 4 and the grouting holes, using theoretical calculations or numerical simulations (e.g., software such as PLAXIS 2D / 3D or FLAC 3D). The grouting holes can be arranged in single or multiple rows according to actual control needs and the calculation results. Multiple rows can be arranged in two, three, or more rows based on theoretical calculations or numerical simulations. Preferably, the line connecting the centers of each row of grouting holes is parallel to the axial direction of the structure to be corrected, and the hole diameter can be 50–60 mm.

[0029] Step 2: Prepare the grouting pipes. Each grouting pipe consists of pipe A and pipe B tied together. The axes of pipe A and pipe B are parallel and their top surfaces are flush. The length of pipe B is greater than the length of pipe A. The area between the bottom wall of pipe B and the bottom wall of pipe A is the grouting expansion zone 2. The size of the grouting expansion zone can be controlled by adjusting the lengths of pipes A and B. Preferably, the length of pipe B is 4-6 meters greater than the length of pipe A.

[0030] Step 3: Cut a groove in the ground at the preset location of the isolation wall 3, and then pour the isolation wall 3 in the groove. The isolation wall is arranged parallel to the building structure. The distance between the outer wall of the isolation wall on the side closer to the building structure and the center line of the grouting hole is 1 to 2 meters. The closer the isolation wall is to the grouting body, the more obvious the deformation control effect on the object to be corrected is, and the smaller the adverse impact on the building structure on the other side.

[0031] The isolation wall is a cement-soil mixing wall. Preferably, depending on the project requirements, steel sections can be inserted into the isolation wall to improve its strength and rigidity. The isolation wall thickness is 1m, and the length of the isolation wall is consistent with the length of each row of grouting holes and the longitudinal length of the grouting holes.

[0032] Step 4: Drill grouting holes at the designated locations using a drilling machine. Use mud slurry to protect the borehole walls to prevent collapse. Ensure that the bottom elevation of the grouting holes is consistent with the theoretical calculations or numerical simulation results.

[0033] Step 5: Excavate foundation pit 4 inside the isolation wall. Simultaneously, based on the measuring points arranged on the structure to be corrected 1, measure the horizontal deformation of the structure in sections using instruments such as a total station or level. When the horizontal deformation exceeds the alarm value set before the foundation pit construction, insert grouting pipes into the grouting holes at the corresponding positions of the horizontal deformation based on the measured horizontal deformation results, and perform the following grouting process to reduce the horizontal deformation of the structure to be corrected to below the alarm value:

[0034] The first step is to inject cement grout through pipe B until cement grout flows out of the grouting hole, ensuring that the entire grouting hole is filled with cement grout.

[0035] The second step is to inject water glass through pipe A, so that the cement slurry and water glass are mixed within the length of pipe A below the surface of the grouting hole, and the hole is sealed; the preferred water-cement ratio of the cement slurry is 0.6 to 0.7.

[0036] The third step is to inject a two-component grout through pipe B to control soil deformation.

[0037] The grouting holes can be arranged in a single row or multiple rows. The positions of the grouting holes in multiple rows are as follows: Figure 3 As shown.

[0038] The two-component slurry is composed of cement slurry and water glass, or a mixture of the two. The preferred volume ratio of cement slurry to water glass in the two-component slurry is 3:1. The mixture of cement slurry and water glass can rapidly solidify and gain strength within a short time.

[0039] In this method, the structure to be corrected can be a tunnel, a foundation pit retaining structure, or other structures.

[0040] like Figure 4 As shown, in one embodiment of the present invention, the grouting pipe is a steel pipe, the length of pipe B is slightly greater than the drilling depth, the top of pipe A is flush with pipe B, the drilling diameter is 50mm, and the bottom is the grouting expansion area. The size of the grouting expansion area can be controlled by adjusting the lengths of pipes A and B.

[0041] like Figure 5 As shown in the numerical simulation results, when there is an isolation wall on the right side of the grouting body, the grouting area expands more to the left (tunnel side) after grouting. This indicates that the isolation wall has a reaction effect, which enhances the effect of grouting in controlling the structure to be corrected and thus reduces the amount of grouting material used. On the right side of the grouting body (excavation pit side), the horizontal displacement of the soil at the corresponding location with the isolation wall is smaller and more uniform than that without the isolation wall. This is because the stiffness of the isolation wall is greater than that of the soil, thus the isolation wall has a shielding effect on the grouting, thereby reducing the impact on the excavation pit on the other side.

[0042] Although preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these modifications are within the scope of protection of the present invention.

Claims

1. A method for controlling deformation of a building structure by combined use of a grouting and a partition wall, characterized by Includes the following steps: Step 1: Before excavating the foundation pit or during the excavation process, obtain the location and number of grouting holes between the foundation pit and the building to be corrected, the range of the grouting expansion zone at the bottom of the grouting holes, and the location and depth of the isolation wall between the foundation pit and the grouting holes through theoretical calculation or numerical simulation. Step 2: Prepare grouting pipes. Each grouting pipe consists of pipe A and pipe B tied together. The axes of pipe A and pipe B are parallel and their top surfaces are flush. The length of pipe B is greater than the length of pipe A. The area between the bottom wall of pipe B and the bottom wall of pipe A is the grouting expansion area. Step 3: Cut a groove in the ground at the preset location of the isolation wall, and then pour the isolation wall in the groove. The isolation wall is arranged parallel to the building structure. The distance between the outer wall of the isolation wall on the side closer to the building structure and the center line of the grouting hole is 1 to 2 meters. The isolation wall is a cement-soil mixing wall. Step 4: Drill grouting holes at the designated locations using a drilling machine, and use mud slurry to protect the drilling walls. Step 5: Excavate the foundation pit inside the isolation wall. Simultaneously, based on the measuring points placed on the structure to be corrected, measure the horizontal deformation of the structure in sections using instruments. When the horizontal deformation exceeds the alarm value set before the foundation pit construction, insert grouting pipes into the grouting holes at the corresponding positions of the horizontal deformation, and perform the following grouting process to reduce the horizontal deformation of the structure to be corrected to below the alarm value: The first step is to inject cement grout through pipe B until cement grout flows out of the grouting hole, ensuring that the entire grouting hole is filled with cement grout. The second step is to inject water glass through pipe A, so that the cement slurry and water glass are mixed within the length of pipe A below the surface of the grouting hole, and the hole is sealed. The third step is to inject a dual-liquid grout through pipe B to control soil deformation. The dual-liquid grout is made by uniformly mixing cement grout and water glass.

2. The method of claim 1, wherein the method of controlling deformation of a construction structure by combined use of a grouting wall and an isolation wall is characterized by: The grouting holes are arranged in a single row or multiple rows. The line connecting the centers of each row of grouting holes is parallel to the axial direction of the structure to be corrected. When there are multiple rows of grouting holes, the fourth step is performed after the third step in step five: During the grouting process, the first to third steps are repeated repeatedly, and grout is injected into the grouting pipes in each row of grouting holes in the order of grouting from farthest to near the structure to be corrected, until the horizontal deformation of the structure to be corrected is reduced to below the alarm value.

3. The method of claim 1 or 2, wherein the method is used for controlling deformation of a construction structure. The water-cement ratio of the cement slurry is 0.6 to 0.

7.

4. The method of claim 1, wherein the method is used for controlling deformation of a construction structure. The volume ratio of cement slurry to water glass in the two-component slurry is 3:

1.

5. The method of claim 4, wherein the method is used for controlling deformation of a construction structure. In each grouting pipe, the length of pipe B is 4 to 6 meters longer than the length of pipe A.

6. The method for controlling the deformation of buildings and structures by combining grouting and isolation walls according to claim 5, characterized in that: Steel sections are inserted into the isolation wall, which is 1m thick and its length is consistent with the longitudinal length of each row of grouting holes.

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