A vertical shaft grouting water-stopping construction method for controlling stratum deformation

Abstract

The present invention provides a shaft grouting and water-stopping construction method for controlling stratum deformation, which belongs to the technical field of water-rich stratum water-stopping reinforcement, and includes the following steps: spraying bottom sealing concrete at the bottom of the shaft 0.5-1.0m above the groundwater level to seal the bottom of the stratum to be excavated; performing inclined hole grouting and water-stopping construction at the four side walls of the shaft; performing straight hole grouting and water-stopping construction at the bottom of the shaft; reinforcing grouting construction in the form of supplementary water-stopping by sleeve valve pipes on the four side walls, and supplementary water-stopping and reinforcement construction by grouting at the bottom of the shaft. A shaft grouting and water-stopping construction method for controlling stratum deformation provided by the present invention injects slurry into the water-rich stratum in sections and in batches by a method of controlling the grouting pressure as the main method and controlling the grouting amount as the auxiliary method, so as to avoid causing large deformation of the surrounding strata. By dividing the grouting construction into two aspects of water-stopping and water-stopping reinforcement according to the function, rapid water-stopping of the water-rich stratum is achieved, and the overall stability of the stratum during excavation is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of water-rich stratum water-stopping reinforcement, and more specifically, relates to a vertical shaft grouting water-stopping construction method for controlling stratum deformation. Background Art

[0002] Before excavation of underground projects such as shafts and foundation pits in water-rich strata, water-stopping structures such as ground-anchored walls are often constructed around the project, or dewatering measures are taken before and during construction to ensure that the excavation work is carried out in a safe and water-free environment. However, in some cases, the construction of ground-anchored walls and dewatering measures are not feasible.

[0003] In the absence of water-stopping structures such as ground-connected walls and precipitation, grouting water-stopping measures are often used before excavation of water-rich strata. However, improper grouting construction will cause significant deformation of the strata around the shaft or water-stopping failure, affecting the safety of the surrounding environment and making it impossible to carry out subsequent excavation work.

[0004] In addition, due to the continuous rise in urban groundwater levels in recent years, the traditional cement-water glass double liquid slurry materials and traditional construction processes in the prior art are difficult to apply. In the actual grouting construction process, the cement-water glass double liquid slurry is injected into the water-rich stratum through a large grouting pressure in order to achieve the purpose of stratum water-stopping reinforcement. This construction method has many uncontrollable factors. For urban spaces, large forced grouting pressure may cause excessive deformation of the stratum, thereby affecting the safety of buildings (structures) around the construction area. In addition, too much slurry injected at one time is not conducive to the dissipation of the pore water pressure of the water-rich stratum. The formation of excess pore water pressure leads to excessive deformation of the stratum and excessive surface uplift. Based on the prior art, many grouting water-stopping projects have shown problems such as surface uplift or excessive stratum deformation, poor slurry injectability, and grouting water-stopping failure in actual construction. Summary of the invention

[0005] The purpose of the present invention is to provide a vertical shaft grouting water-stopping construction method for controlling stratum deformation, aiming to solve the technical problem that the existing construction technology will show excessive stratum deformation in actual construction.

[0006] To achieve the above object, the technical solution adopted by the present invention is: to provide a vertical shaft grouting water-stopping construction method for controlling stratum deformation, comprising:

[0007] Step 1: spray bottom concrete at the bottom of the shaft 0.5-1.0m above the groundwater level to seal the bottom of the stratum to be excavated. The bottom concrete is connected with the shaft side wall concrete that has been completed in the early stage to form a closed water-stopping structure;

[0008] Step 2: Perform grouting and water-stopping construction of inclined holes at the side walls of the four sides of the shaft, wherein the types of inclined holes include grouting holes and pressure relief holes; the grouting and water-stopping construction adopts a backward grouting method combined with a segmented forward grouting method, and adopts a side wall circumference circulation water-stopping grouting method, and each hole is completed by grouting 2-4 times;

[0009] Step 3: Grouting and water-stopping of straight holes at the bottom of the shaft, wherein the types of straight holes include grouting holes and pressure relief holes; the grouting and water-stopping construction adopts a backward grouting method combined with a segmented forward grouting method; a bottom position circulating water-stopping grouting method is adopted, and each hole is grouted 1-3 times to complete the grouting operation;

[0010] Step 4: Grouting of the four side walls adopts the form of sleeve valve pipe supplementary water-stopping reinforcement grouting. During the sleeve valve pipe supplementary water-stopping operation, a segmented backward grouting method is adopted, and the length of each grouting section is 0.1-0.5m;

[0011] Step 5: Grouting is performed on the bottom of the shaft to supplement the water-stopping reinforcement. During the construction process, the drill rod is grouted in sections with a backward grouting method. The length of each section is 0.1-0.5m.

[0012] Preferably, in step 2 and step 4, the single-hole single-time grouting volume is calculated according to the following formula:

[0013]

[0014] Among them, Q1 is the single-hole single-time grouting volume at the four side walls of the shaft, N1 is the number of single-hole grouting times, and the value range is 3 to 5; N k1 is the number of designed grouting holes at the four side walls of the shaft, V1 is the grouting soil volume at the four side walls of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.4

[0015] Preferably, in step 3 and step 5, the single-hole single-time grouting volume is calculated according to the following formula:

[0016]

[0017] Among them, Q2 is the single-hole single-time grouting volume at the bottom of the shaft, N2 is the single-hole grouting times, and the value range is 2 to 4; N k2 is the designed number of grouting holes at the bottom of the shaft, V2 is the grouting soil volume at the bottom of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.4.

[0018] Preferably, in step 2 and step 3, the backward grouting method combined with the segmented forward grouting method is as follows: if the amount of water gushing from the hole mouth is large during the drilling process, the drilling is stopped, and the grouting water-stopping operation is immediately performed until there is no obvious water gushing from the hole mouth and the drilling is continued. When the drilling reaches the designed hole depth, the segmented backward grouting operation of pulling the rod is performed.

[0019] Preferably, in step 4 and step 5, the segmented backward grouting method is specifically as follows: grouting is performed after drilling to the designed depth, and when the grouting pressure increases significantly or reaches the designed grouting volume, the drill rod is lifted upward by 0.1-0.5m, and then the two construction processes of "grouting and lifting the drill rod" are repeated until the drill rod is pulled out of the formation.

[0020] Preferably, in step 4, multiple 45° inclined holes are drilled at the junction of the four side walls and the bottom of the shaft at intervals of 0.5-0.8m. After the sleeve valve pipe is installed in the inclined hole, a grouting plug with a grouting core pipe is lowered into the sleeve valve pipe, and then grouting is carried out by a segmented backward grouting method.

[0021] Preferably, in step 2, the inclined hole grouting water-stopping construction constructs 2-3 boreholes at a time, wherein any one borehole is a grouting hole, and the remaining boreholes are pressure relief holes, and the distance between the grouting holes and the pressure relief holes is 1.5-2.0m.

[0022] Preferably, the grouting water-stopping material can be one or more of nano-modified ultrafine cement slurry and modified water glass double liquid slurry.

[0023] Preferably, the scope of grouting water-stopping reinforcement is 2-5m outward from the structural lines of the four side walls of the shaft; and 2-5m downward from the bottom line of the designed structure of the shaft.

[0024] Preferably, the method further comprises: monitoring the ground deformation around the shaft during the grouting construction, wherein the monitoring plane range is not less than 1.5 times the depth of the excavated shaft, and the monitoring frequency is 2 times / d.

[0025] The beneficial effect of the vertical shaft grouting and water-stopping construction method for controlling stratum deformation provided by the present invention is that: compared with the prior art, the vertical shaft grouting and water-stopping construction method for controlling stratum deformation of the present invention injects slurry into the water-rich stratum in sections and in batches by controlling the grouting pressure as the main method and controlling the grouting amount as the auxiliary method, so as to avoid excessive grouting pressure or excessive amount of slurry injected at one time causing large deformation of the surrounding stratum. By dividing the grouting construction into two aspects, namely, water-stopping and water-stopping reinforcement, rapid water-stopping of the water-rich stratum is achieved, and the overall stability of the stratum during excavation is ensured. By performing rigid sleeve valve pipe grouting operations at the junction of the four side walls and the bottom surface of the side wall, while ensuring that the slurry can achieve the effect of penetration and water-stopping reinforcement in the stratum, the rigid sleeve valve pipe retained in the stratum can increase the overall stiffness and stability of the stratum around the vertical shaft, further reducing stratum deformation and the convergence of the overall structure of the vertical shaft. The required tools and machines are easy to obtain and highly maneuverable. Without constructing water-stopping structures such as ground-connected walls and without precipitation, the subsequent shaft excavation can be carried out in a safe and water-free environment. It can be used not only for grouting and water-stopping of shafts in water-rich strata, but also for grouting and water-stopping of deep holes in shallow-buried tunnels in cities in water-rich strata. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic flow chart of a vertical shaft grouting water-stopping construction method for controlling stratum deformation provided by an embodiment of the present invention;

[0028] Figure 2 It is a plan view of grouting and water-stopping reinforcement of the water-rich stratum of the vertical shaft in the present invention;

[0029] Figure 3 This is a vertical elevation view of the grouting and water-stopping reinforcement of the water-rich stratum in the vertical shaft of the present invention;

[0030] Figure 4 It is a schematic diagram of the division of grouting positions for water-rich formations in the vertical shaft of the present invention;

[0031] Figure 5 Excavation effect after grouting water-stopping construction (constructed according to Example 1) in water-rich fine sand stratum Figure 1 ;

[0032] Figure 6 Excavation effect after grouting water-stopping construction (constructed according to Example 1) in water-rich fine sand stratum Figure 2 ;

[0033] Figure 7 On-site water accumulation after traditional grouting water-stopping construction Figure 1 ;

[0034] Figure 8 On-site water accumulation after traditional grouting water-stopping construction Figure 2 ;

[0035] Fig. 9 According to Example 1, the monitoring situation level data analysis during the construction process is performed;

[0036] Fig.10 According to Example 1, the monitoring situation level data analysis during the construction process is performed 2;

[0037] Fig.11 According to Example 1, the monitoring situation level data analysis during the construction process is performed three times;

[0038] Fig.12 According to Example 1, the monitoring situation level data analysis during the construction process is performed four times;

[0039] Fig.13 is a diagram of cumulative settlement during the construction process according to Example 1;

[0040] Fig.14 The layout diagram of monitoring points when the third party issues the project monitoring report during the construction process according to Example 1;

[0041] Fig.15 This is the data table of the subsidence of the nearby subway track bed monitored on August 11, 22;

[0042] Fig.16 This is the data table of the subsidence of the roadbed near the subway monitored on November 14, 22. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] During grouting water-stopping construction, if the grouting pressure is too high or the amount of slurry injected at one time is too large, the slurry will push the surrounding soil and cause the soil to produce a large excess pore water pressure. Its adverse effects are often manifested as large deformation of the surrounding strata. As the excess pore water pressure dissipates, the surrounding strata will produce a large area of ​​settlement. Such repeated disturbance of the soil is not conducive to the stability and deformation control of the strata. The purpose of the present invention is to provide a grouting water-stopping construction method for controlling strata deformation and ensuring safe waterless excavation of urban tunnel shafts. In particular, for grouting water-stopping construction of water-rich sand layers, the invention can effectively solve the problems of difficulty in slurry injection, poor water-stopping reinforcement effect of water-rich strata, and excessive strata deformation caused by excessive grouting pressure or grouting amount.

[0045] Please also read Figures 1 to 12 Now, a vertical shaft grouting water-stopping construction method for controlling stratum deformation provided by the present invention is described. The vertical shaft grouting water-stopping construction method for controlling stratum deformation is to first complete the vertical shaft side wall concrete before the vertical shaft grouting water-stopping construction. The vertical shaft grouting water-stopping construction method for controlling stratum deformation includes the following steps:

[0046] S1. Spray bottom concrete at the bottom of the shaft 0.5-1.0m above the groundwater level to seal the bottom of the stratum to be excavated. The bottom concrete is connected with the shaft side wall concrete that has been completed in the early stage to form a closed water-stopping structure;

[0047] It should be noted that the height depends on the actual situation. In order to prevent difficulties in the subsequent bottom sealing concrete application, it is generally 0.5-1.0m above the groundwater level. Or when the groundwater level is first seen during the actual excavation process, the bottom sealing concrete is sprayed to seal the bottom of the stratum to be excavated.

[0048] In step S1, the thickness of the bottom seal concrete is 0.3-0.5 and the strength grade is C20-C25.

[0049] S2. Carry out grouting and water-stopping construction of inclined holes at the side walls of the four sides of the shaft. The types of inclined holes include grouting holes and pressure relief holes. The grouting and water-stopping construction adopts the backward grouting method combined with the segmented forward grouting method, and adopts the method of circulating water-stopping grouting around the side walls. Each hole is completed by grouting 2-4 times;

[0050] In step S2, the inclined hole grouting water-stopping construction constructs 2-3 boreholes at a time, any of which is a grouting hole, and the remaining boreholes are pressure relief holes (also serving as grouting holes). The pressure relief holes also serve as grouting holes, and are arranged in the same row as the grouting holes. Generally, the positions of the grouting holes and the pressure relief holes are: grouting holes-pressure relief holes or grouting holes-pressure relief holes-grouting holes. The distance between the grouting holes and the pressure relief holes is 2 times the hole spacing, i.e. 1.5-2.0m. If the distance between the grouting holes and the pressure relief holes is too small, the slurry will easily block the holes, resulting in poor pressure relief effect. The distance between the grouting holes and the pressure relief holes is selected to be 2 times the grouting hole spacing, i.e. when the distance is 1.5-2.0m, the slurry can be driven to diffuse outward while the pressure is released, effectively ensuring the grouting water-stopping range. If the distance is too large, it is difficult to ensure the pressure relief effect near the grouting holes. The depth of the grouting holes is the design depth, and the depth of the pressure relief holes is 0.3-0.5m. It can ensure that groundwater will gush out. Circulating water-stop grouting around the side walls 2-3 times can strictly prevent the ground uplift around the shaft structure.

[0051] S3. The vertical shaft bottom surface adopts straight hole grouting water-stopping construction, among which the types of straight holes include grouting holes and pressure relief holes; the grouting water-stopping construction adopts the backward type combined with the segmented forward grouting method; the bottom surface position adopts the method of circulating water-stopping grouting, and each hole is completed by grouting 1-3 times;

[0052] In step 3, two holes can be constructed in one straight hole grouting water stop construction, one of which is a grouting hole and the other is a pressure relief hole. The distance between the grouting hole and the pressure relief hole is 1.5-2.0m, and the depth of the pressure relief hole is 0.3-0.5m. The bottom surface position is circulated for 1-2 times of water stop grouting. It can prevent the bottom surface of the shaft from being too large.

[0053] Grouting water-stopping construction adopts the backward grouting method combined with the segmented forward grouting method. If the amount of water gushing out from the hole mouth is large during the drilling process, stop drilling and immediately carry out grouting water-stopping operations until there is no obvious water gushing out from the hole mouth. When drilling to the designed hole depth, carry out the rod-pulling backward grouting operation, and control the rod-pulling grouting length of each time to be 0.1-0.5m;

[0054] In step S3, the number of straight holes is set to be multiple, and the multiple straight holes are arranged in a plum blossom shape;

[0055] It should be noted that in step S2 and step S3, the backward grouting method combined with the segmented forward grouting method is as follows: if the amount of water gushing from the hole mouth is large during the drilling process, the drilling is stopped, and the grouting water-stopping operation is immediately carried out until there is no obvious water gushing from the hole mouth and the drilling is continued; when drilling to the designed hole depth, the segmented backward grouting operation of pulling rods is carried out.

[0056] S4. Use sleeve valve pipes to supplement water-stopping to reinforce the grouting construction on the four side walls. During the sleeve valve pipe supplementary water-stopping operation, the segmented backward grouting method is adopted, and the length of each segment of grouting is 0.1-0.5m;

[0057] In step S4, 45° inclined holes are drilled at the junction of the four side walls and the bottom of the shaft at a spacing of 0.5-0.8m. Then the sleeve valve pipe is installed in the inclined hole, and a stopper with a grouting core pipe is lowered into the sleeve valve pipe. The grouting pressure during the grouting process is 0.3MPa-0.5MPa.

[0058] The stop plug is pressurized to 2.5MPa by a hand pump or an electric pump to seal the upper opening of the sleeve valve pipe. Then the grouting operation is carried out. After the grouting is completed, the pressure in the stop plug is released and it is lifted upward with the grouting core pipe.

[0059] In steps S2 and S4, the single-hole single-time grouting volume is calculated according to the following formula:

[0060]

[0061] Among them, Q1 is the single-hole single-time grouting volume at the four side walls of the shaft, N1 is the number of single-hole grouting times, and the value range is 3 to 5; N k1 is the designed number of grouting holes at the four side walls of the shaft, V1 is the grouting soil volume at the four side walls of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.4.

[0062] In step S4, a grout overflow hole is provided on the rigid sleeve valve tube; specifically, the rigid sleeve valve tube is a seamless steel tube with a pointed cone head at the bottom, and the steel tube wall and the pointed cone head are both provided with grout overflow holes. The casing material is a mixture of cement, bentonite and water, and the mass mix ratio is cement: bentonite: water = 1:1:2.

[0063] In step 4, grouting is performed by using a segmented backward grouting method;

[0064] The scope of grouting water-stopping reinforcement is 2-5m outward from the structural line of the four side walls of the shaft, and 2-5m downward from the bottom line of the shaft design structure. The scope of grouting water-stopping reinforcement is 2-3m outward from the structural line of the four side walls of the shaft, and 2-3m downward from the bottom line of the shaft design structure.

[0065] S5. Grouting is used to supplement the water-stopping reinforcement construction on the bottom of the vertical shaft. During the construction process, the drill rod segmented backward grouting method is adopted. The length of each grouting section is 0.1-0.5m; the spacing between the drill rod backward water-stopping reinforcement grouting holes is 0.6-1.0m.

[0066] In step S5, the grouting pressure during the grouting process is 0.3-0.5 MPa.

[0067] In steps S3 and S5, the single-hole single-time grouting volume is calculated according to the following formula:

[0068]

[0069] Among them, Q2 is the single-hole single-time grouting volume at the bottom of the shaft, N2 is the single-hole grouting times, and the value range is 2 to 3; N k2 is the designed number of grouting holes at the bottom of the shaft, V2 is the grouting soil volume at the bottom of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.4.

[0070] In step S5, the grouting standard for the single hole of the shaft bottom grouting water-stopping reinforcement construction is: the grouting pressure is maintained at 0.5MPa-0.8MPa for more than 10 minutes and the grouting volume is less than 5L / min.

[0071] It should be noted that in step S4 and step S5, the segmented backward grouting method is specifically as follows: grouting operation is carried out after drilling to the designed depth. When the grouting pressure increases significantly or reaches the designed grouting volume, the drill rod is lifted upward by 0.1-0.5m, and then the two construction processes of "grouting and lifting the drill rod" are repeated until the drill rod is pulled out of the formation.

[0072] In step S2 and step S3, the grouting water-stopping material is selected according to different formation conditions. Specifically, the grouting water-stopping material can be one or more of nano-modified ultrafine cement slurry and modified water glass double liquid slurry. More specifically, nano-modified ultrafine cement slurry is selected for water-rich powder fine sand formation. Modified water glass double liquid slurry is selected for grouting water-rich formation other than water-rich powder fine sand.

[0073] The mass ratio of nano-modified ultrafine cement slurry can be water: ultrafine cement: nano-magnesium oxide: siloxane: polyethylene glycol (average molecular weight 1000): ultrafine fly ash: = 100-120:80:1.5:5:1-3:20. The specific preparation method is as follows: water, siloxane, polyethylene glycol, and nano-magnesium oxide are poured into a stirrer according to the proportion, and stirred at 30-50°C and 500rmp for 10-15min to obtain a suspension; ultrafine fly ash and ultrafine cement are added to the suspension in proportion in sequence, and the speed is adjusted to 100rmp and stirred for 10-20min to obtain nano-modified ultrafine cement slurry.

[0074] Advantages of nano-modified ultrafine cement slurry: Nano-magnesium oxide added to cement-based grouting materials can significantly control the plastic shrinkage cracks of the slurry consolidation body, improve the shrinkage resistance and crack resistance of the consolidation body, and reduce later leakage; polyethylene glycol can form a film on the slurry surface and improve the density and anti-dispersion of cement, so that it is not easy to be diluted by water during the grouting process to prevent the loss of slurry. In addition, a higher amount of polyethylene glycol can play a retarding role. In addition to forming silica nanoparticles, siloxane can also play an organic-siloxane-inorganic interface role to improve the compatibility of inorganic and organic components. Ultrafine fly ash has a high reaction activity. The active SiO2 reacts with the Ca(OH)2 generated by cement hydration to form hydrated calcium silicate and other gels that fill the pores of the soil, which can improve the density of the soil and reduce the porosity of the hardened slurry.

[0075] The modified water glass double liquid slurry can be composed of liquid A and liquid B, wherein liquid A is a phosphoric acid solution diluted with water to a mass fraction of 5.5%-7.0%, and liquid B is a water glass solution diluted with water to a concentration of 20 degrees Baume. During grouting, liquid A and liquid B are mixed in a volume ratio of 1:1. The solidification time of modified water glass double liquid slurry is 3-5s. During the first grouting and water-stopping construction, a phosphoric acid solution with a corresponding mass fraction of 5.5% of liquid A is used at the side wall and bottom surface, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 3s; during the second grouting and water-stopping construction at the side wall, a phosphoric acid solution with a corresponding mass fraction of 6.25% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 4s; during the second grouting and water-stopping construction at the bottom surface, a phosphoric acid solution with a corresponding mass fraction of 7.0% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 5s; during the third grouting and water-stopping construction at the side wall, a phosphoric acid solution with a corresponding mass fraction of 7.0% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 5s.

[0076] After the grouting water-stopping construction is completed, compensatory grouting water-stopping reinforcement construction is required in the original stratum.

[0077] Example 1

[0078] The grouting water-stopping material is nano-modified ultrafine cement slurry. The slurry mass ratio is water: ultrafine cement: nano-magnesium oxide: siloxane: polyethylene glycol (average molecular weight 500): ultrafine fly ash: = 100-120:80:1.5:5:1-3:20. The material properties are as follows:

[0079]

[0080]

[0081] In steps S4 and S5, the grouting water-stopping reinforcement material is ordinary silicate cement slurry or ultra-fine cement slurry, and the water-cement ratio of the cement slurry is 1-1.2:1.

[0082] In this vertical shaft grouting water-stopping construction method for controlling stratum deformation, after grouting is completed, inspection holes are set according to 5% to 10% of the total grouting holes. The inspection holes are obtained by core sampling. The core samples taken need to be tested for strength and permeability. For example, the unconfined compressive strength is ≥0.5MPa and the permeability coefficient is ≤10 -6 cm / s, the grouting water-stopping reinforcement effect is achieved, otherwise cement-water glass double liquid slurry should be injected.

[0083] In this vertical shaft grouting and water-stopping construction method for controlling stratum deformation, after the construction of each row of grouting holes is completed, a borehole exploration device is lowered after drilling holes at the row positions, and the boreholes are inspected by in-hole imaging. If there is no hole collapse in the boreholes, and the slurry is evenly filled and the hole walls are relatively dry, it means that the grouting effect has been achieved. The number of inspection holes in each row is not less than 2.

[0084] In this vertical shaft grouting water-stopping construction method for controlling ground deformation, the depth of one cycle of grouting is 8m-10m, and the excavation depth after grouting is 6m-8m, leaving at least 2m thick overlapping grouting soil layer. After one cycle of excavation construction is completed, the next cycle of grouting construction is carried out. Before each cycle of grouting, a grouting stop structure with a thickness of 0.3m is applied.

[0085] In this shaft grouting water-stopping construction method for controlling stratum deformation, the surface deformation monitoring around the shaft should be strengthened during the entire grouting construction process. The monitoring plane range should not be less than 1.5 times the depth of the excavated shaft, and the monitoring frequency is 2 times / d.

[0086] The invention provides a vertical shaft grouting and water-stopping construction method for controlling stratum deformation. Compared with the prior art, the invention mainly controls the grouting pressure and controls the grouting amount as a supplement, and injects slurry into the water-rich stratum in sections and in batches, so as to avoid excessive grouting pressure or excessive slurry injection at one time, which may cause large deformation of the surrounding stratum. By dividing the grouting construction into two aspects, namely, water-stopping and water-stopping reinforcement, the rapid water-stopping of the water-rich stratum can be achieved, and the overall stability of the stratum during excavation can be ensured. By performing the rigid sleeve valve pipe grouting operation at the junction of the four side walls and the bottom surface of the side wall, the slurry can achieve the penetration and water-stopping reinforcement effect in the stratum, and the rigid sleeve valve pipe retained in the stratum can increase the overall rigidity and stability of the stratum around the vertical shaft, further reducing the stratum deformation and the overall structural convergence of the vertical shaft. The required tools and machines are easy to obtain and have strong operability. Under the premise of not constructing water-stopping structures such as ground-connected walls and not dropping water, the subsequent vertical shaft excavation operation can be ensured to be carried out in a safe and waterless environment. It can not only be used for grouting and water stopping in vertical shafts in water-rich strata, but also for grouting and water stopping in deep holes of shallow buried tunnels in cities in water-rich strata.

[0087] The following are examples and Figures 1 to 4 Further support and illustrate the technical solution of the present invention.

[0088] A vertical shaft grouting water-stopping construction method for controlling stratum deformation comprises the following steps:

[0089] Example 1

[0090] For water-rich gravel formations, see Figures 1 to 16 , spray grade C20 concrete on the bottom of the shaft 0.5m above the groundwater level to carry out bottom sealing operation. The concrete serves as the grouting structure for subsequent grouting construction. The thickness of the grouting structure is 0.3m and it is effectively connected with the completed shaft side wall concrete.

[0091] See also Figure 2 , 3 First, grouting and water-stopping construction is carried out. Two holes are drilled, one hole is injected, and one hole is left as a pressure relief hole during the grouting process. The distance between the grouting hole and the pressure relief hole is 1.6m, and the depth of the pressure relief hole is 0.5m. The drilling and grouting sequence is to first grout the inclined holes at the four side walls, and then grout the straight holes at the bottom of the shaft. The straight holes at the bottom of the shaft are arranged in a plum blossom shape. The grouting and water-stopping material is modified water glass double liquid slurry, in which liquid A is a phosphoric acid solution diluted with water to a mass fraction of 5.5%-7.0%, and liquid B is a water glass solution diluted with water to a concentration of 20 degrees Baume. During grouting, liquid A and liquid B are mixed in a volume ratio of 1:1. The solidification time of modified water glass double liquid slurry is 3-5s. During the first grouting and water-stopping construction, a phosphoric acid solution with a corresponding mass fraction of 5.5% of liquid A is used at the side wall and bottom surface, and liquid B is a water glass solution diluted with water to a concentration of 20 degrees Baume. During grouting, liquid A and liquid B are mixed in a volume ratio of 1:1, and the solidification time of the double liquid slurry is 3s; during the second grouting and water-stopping construction at the side wall, a phosphoric acid solution with a corresponding mass fraction of 6.25% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 4s; during the second grouting and water-stopping construction at the bottom surface, a phosphoric acid solution with a corresponding mass fraction of 7.0% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 5s; during the third grouting and water-stopping construction at the side wall, a phosphoric acid solution with a corresponding mass fraction of 7.0% of liquid A is used, and the proportion of liquid B remains unchanged, and the solidification time of the double liquid slurry is 5s.

[0092] The side walls and the bottom surface are both repeatedly grouted to stop water. The number of single-hole grouting water-stopping at the side wall position is 3 times, and the number of single-hole grouting water-stopping at the bottom surface position is 2 times. During the grouting process, the grouting pressure and grouting volume are strictly controlled, and the grouting pressure is mainly used, and the grouting volume is supplemented. After the drilling rig drills to the designed depth, the drill overflow hole is used for backward grouting. When the grouting pressure is too large or reaches a certain grouting volume, the drill rod is lifted. The lifting height of each section is 0.2m. After each row of grouting is completed, the next grouting is carried out at the original drilling position. After the grouting of one row of grouting holes is completed, the next row of grouting operations is carried out. The grouting pressure control value is 0.5MPa.

[0093] Then, the rigid sleeve valve pipe grouting and water-stopping reinforcement construction of the four side walls was carried out. At the junction of the four side walls and the bottom of the shaft, 45° inclined holes were drilled at intervals of 0.5m. After the sleeve valve pipe was installed in the inclined hole, the stop plug with the grouting core pipe was lowered, and then the shell material was put between the hole wall and the sleeve valve pipe. The segmented backward grouting method was adopted, and the grouting length of each section was 0.2m. The stop plug was pressurized to 2.5MPa by a hand pump to close the upper mouth of the sleeve valve pipe, and then the grouting core pipe was injected with slurry. After the grouting of this section was completed, the grouting core pipe was lifted by 0.2m, and the stop plug pressurization and core pipe grouting operations were repeated.

[0094] Then, grouting and water-stopping reinforcement construction is carried out on the bottom of the shaft, and the drill rod is used for segmented backward grouting. During the grouting process, the grouting pressure is 0.3MPa~0.5MPa, and the length of each grouting section is 20cm. The standard for ending grouting for a single hole is that the grouting pressure is maintained at 0.5MPa~0.8MPa for more than 10 minutes and the grouting volume is less than 5L / min.

[0095] In order to prevent excessive slurry volume injected into the water-rich stratum from causing excessive stratum uplift, the single-hole single-time grouting volume needs to be strictly controlled. The single-hole single-time grouting volume is calculated according to the following formula:

[0096] (1) Grouting volume at the four side walls:

[0097]

[0098] Among them, Q1 is the single-hole single-time grouting volume at the four side walls of the shaft, N1 is the number of single-hole grouting times, which is taken as 4; N k1 is the designed number of grouting holes at the four side walls of the shaft, V1 is the grouting soil volume at the four side walls of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, which is 0.8, and β is the slurry loss coefficient, which is taken as 1.3.

[0099] (2) Grouting volume at the bottom of the shaft:

[0100]

[0101] Among them, Q2 is the single-hole single-time grouting volume at the bottom of the shaft, N2 is the single-hole grouting times, which is taken as 3; N k2 is the designed number of grouting holes at the bottom of the shaft, V2 is the grouting soil volume at the bottom of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient which is 0.8, and β is the slurry loss coefficient which is 1.3.

[0102] The grouting water-stopping reinforcement material is ordinary Portland cement slurry with a water-cement ratio of 1:1.

[0103] Example 2

[0104] For water-rich fine sand formations, see Figure 1 , spray grade C20 concrete on the bottom of the shaft 0.5m above the groundwater level to carry out bottom sealing operation. The concrete serves as the grouting structure for subsequent grouting construction. The thickness of the grouting structure is 0.3m and it is effectively connected with the completed shaft side wall concrete.

[0105] See also Figure 2 , 3 First, grouting water-stopping construction is carried out. The method of drilling 1 hole and grouting 1 hole is adopted. 1 hole is reserved as the pressure relief hole during the grouting process. The distance between the grouting hole and the pressure relief hole is 1.6m, and the depth of the pressure relief hole is 0.5m. The drilling and grouting sequence is to first grout the inclined holes at the four side walls, and then grout the straight holes at the bottom of the shaft. The straight holes at the bottom of the shaft are arranged in a plum blossom shape. The grouting water-stopping material is nano-modified ultrafine cement slurry, and the slurry mass ratio is water: ultrafine cement: nano-magnesium oxide: siloxane: polyethylene glycol (average molecular weight 500): ultrafine fly ash: = 100:80:1.5:5:1:20.

[0106] The side walls and the bottom surface are both repeatedly grouted to stop water. The number of single-hole grouting water-stopping at the side wall position is 4 times, and the number of single-hole grouting water-stopping at the bottom surface position is 3 times. During the grouting process, the grouting pressure and grouting volume are strictly controlled, and the grouting pressure is mainly used, and the grouting volume is supplemented. After the drilling rig drills to the designed depth, the drill overflow hole is used for backward grouting. When the grouting pressure is too large or reaches a certain grouting volume, the drill rod is lifted. The lifting height of each section is 0.1m. After each row of grouting is completed, the next grouting is carried out at the original drilling position. After the grouting of one row of grouting holes is completed, the next row of grouting operations is carried out. The grouting pressure control value is 0.3MPa.

[0107] Then, the rigid sleeve valve pipe grouting and water-stopping reinforcement construction of the four side walls was carried out. At the junction of the four side walls and the bottom of the shaft, 45° inclined holes were drilled at a spacing of 0.5m. After the sleeve valve pipe was installed in the inclined hole, the stop plug with the grouting core pipe was lowered, and then the shell material was put between the hole wall and the sleeve valve pipe. The segmented backward grouting method was adopted, and the grouting length of each section was 0.1m. The stop plug was pressurized to 2.5MPa by a hand pressure pump to close the upper mouth of the sleeve valve pipe, and then the slurry was injected into the grouting core pipe. After the grouting of this section was completed, the grouting core pipe was lifted by 0.1m, and the stop plug pressurization and core pipe grouting operations were repeated.

[0108] Then, grouting and water-stopping reinforcement construction is carried out on the bottom of the shaft, and the drill rod is used for segmented backward grouting. During the grouting process, the grouting pressure is 0.2MPa~0.3MPa, and the length of each grouting section is 10cm. The standard for ending grouting for a single hole is that the grouting pressure is maintained at 0.3MPa~0.5MPa for more than 10 minutes and the grouting volume is less than 5L / min.

[0109] In order to prevent excessive slurry volume injected into the water-rich stratum from causing excessive stratum uplift, the single-hole single-time grouting volume needs to be strictly controlled. The single-hole single-time grouting volume is calculated according to the following formula:

[0110] (1) Grouting volume at the four side walls:

[0111]

[0112] Among them, Q1 is the single-hole single-time grouting volume at the four side walls of the shaft, N1 is the number of single-hole grouting times, which is taken as 5; N k1 is the designed number of grouting holes at the four side walls of the shaft, V1 is the grouting soil volume at the four side walls of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, which is 0.8, and β is the slurry loss coefficient, which is taken as 1.2.

[0113] (2) Grouting volume at the bottom of the shaft:

[0114]

[0115] Among them, Q2 is the single-hole single-time grouting volume at the bottom of the shaft, N2 is the single-hole grouting times, which is taken as 4; N k2 is the designed number of grouting holes at the bottom of the shaft, V2 is the grouting soil volume at the bottom of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient which is 0.8, and β is the slurry loss coefficient which is 1.2.

[0116] The grouting water-stopping reinforcement material is ultra-fine cement slurry with a water-cement ratio of 1:1.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vertical shaft grouting water-stopping construction method for controlling stratum deformation, characterized in that: The following steps are involved: Step 1: spray bottom concrete at the bottom of the shaft 0.5-1.0m above the groundwater level to seal the bottom of the stratum to be excavated. The bottom concrete is connected with the shaft side wall concrete that has been completed in the early stage to form a closed water-stopping structure; Step 2: Perform grouting and water-stopping construction of inclined holes at the side walls of the four sides of the shaft, wherein the types of inclined holes include grouting holes and pressure relief holes; the grouting and water-stopping construction adopts a backward grouting method combined with a segmented forward grouting method, and adopts a side wall circumference circulation water-stopping grouting method, and each hole is completed by grouting 2-4 times; Step 3: Grouting and water-stopping of straight holes at the bottom of the shaft, wherein the types of straight holes include grouting holes and pressure relief holes; the grouting and water-stopping construction adopts a backward grouting method combined with a segmented forward grouting method; a bottom position circulating water-stopping grouting method is adopted, and each hole is grouted 1-3 times to complete the grouting operation; Step 4: Use sleeve valve pipes to supplement water-stopping to reinforce the grouting construction on the four side walls. During the sleeve valve pipe supplementary water-stopping operation, a segmented backward grouting method is used, and the length of each grouting section is 0.1-0.5m; Step 5: Grouting to supplement water-stopping reinforcement on the bottom of the shaft. During the construction process, the drill rod is grouted in sections with a length of 0.1-0.5m for each section. In step 2 and step 3, the backward grouting method combined with the segmented forward grouting method is as follows: if the amount of water gushing out of the hole mouth is large during the drilling process, stop drilling and immediately carry out grouting to stop water, and continue drilling after there is no obvious water gushing out of the hole mouth; when drilling to the designed hole depth, perform segmented backward grouting operation by pulling rods.

2. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: In step 2 and step 4, the single hole single grouting volume is calculated according to the following formula: Among them, Q1 is the single-hole single-time grouting volume at the four side walls of the shaft, N1 is the number of single-hole grouting times, and the value range is 3 to 5; N k1 is the designed number of grouting holes at the four side walls of the shaft, V1 is the grouting soil volume at the four side walls of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.

4.

3. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: In step 3 and step 5, the single hole single grouting volume is calculated according to the following formula: Among them, Q2 is the single-hole single-time grouting volume at the bottom of the shaft, N2 is the single-hole grouting times, and the value range is 2 to 4; N k2 is the designed number of grouting holes at the bottom of the shaft, V2 is the grouting soil volume at the bottom of the shaft, n is the soil porosity within the grouting range, α is the formation filling coefficient, ranging from 0.6 to 1.0, and β is the slurry loss coefficient, ranging from 1.2 to 1.

4.

4. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: In step 4 and step 5, the segmented backward grouting method is specifically as follows: after drilling to the designed depth, grouting operation is carried out. When the grouting pressure increases significantly or reaches the designed grouting volume, the drill rod is lifted upward by 0.1-0.5m, and then the two construction processes of "grouting and lifting the drill rod" are repeated until the drill rod is pulled out of the formation.

5. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: In step 4, multiple 45° inclined holes are drilled at the junction of the four side walls and the bottom of the shaft at intervals of 0.5-0.8m. After the sleeve valve pipe is installed in the inclined hole, a grouting plug with a grouting core pipe is lowered into the sleeve valve pipe, and then grouting is carried out using a segmented backward grouting method.

6. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: In step 2, the inclined hole grouting water-stopping construction constructs 2-3 boreholes at a time, wherein any one borehole is a grouting hole, and the remaining boreholes are pressure relief holes, and the distance between the grouting holes and the pressure relief holes is 1.5-2.0m.

7. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: The grouting water-stopping material can be one or more of nano-modified ultrafine cement slurry and modified water glass double liquid slurry.

8. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: The scope of grouting water-stopping reinforcement is 2-5m outward from the structural lines of the four side walls of the shaft; and 2-5m downward from the bottom line of the designed structure of the shaft.

9. A vertical shaft grouting water-stopping construction method for controlling stratum deformation as claimed in claim 1, characterized in that: Also includes: During the grouting construction, the surface deformation around the shaft is monitored. The monitoring plane range is not less than 1.5 times the depth of the excavated shaft, and the monitoring frequency is 2 times / d.

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