High-pressure water-rich section surrounding rock grouting construction method

Abstract

The invention discloses a high-pressure water-rich section surrounding rock grouting construction method which comprises the following steps: carrying out advanced geological forecast on surrounding rock, and describing geological conditions; drilling an advanced deep hole in the tunnel face to obtain a core sample, and discharging part of underground water through the advanced deep hole; performing a physical and mechanical test on the obtained core sample to obtain physical and mechanical characteristics and permeability characteristics of a rock-soil body, dividing the surrounding rock into a loose damage area, an elastic-plastic deformation area and an elastic deformation micro-disturbance area by combining an advanced geological forecast detection result, a geological condition description result and theoretical analysis, and locking a grouting area; and advanced deep hole dynamic grouting is conducted on the locked grouting area, specifically, a grouting anti-seepage wall is formed between the elastic deformation micro-disturbance area and the elastic-plastic deformation area, a grouting reinforcement area is formed in the loose damage area, and a grouting reinforcement area is formed between the grouting reinforcement area and the grouting anti-seepage wall. The method is high in pertinence, and the problems of large deformation, water burst and the like of surrounding rock when the tunnel passes through the high-pressure water-rich fault fracture zone can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, in particular to a high-pressure water-rich section surrounding rock grouting construction method. Background Art

[0002] As the number of tunnels built in my country increases, geological conditions become increasingly complex. During the construction process, it is inevitable to encounter adverse geological conditions such as dense joints, high-pressure water-rich fault zones, and complex water bodies.

[0003] The high-water-pressure fault fracture zone is a complex geological condition often encountered in the tunnel construction process. This type of geological condition has the characteristics of high groundwater pressure and poor surrounding rock crushing stability. If traditional advance reinforcement measures are not in place, geological disasters such as surrounding rock collapse and mud and water gushing are very likely to occur, and the construction safety risk is extremely high.

[0004] At present, the construction and grouting reinforcement technology for high-pressure water-rich fault zones is relatively simple. Without fully exploring the engineering geology and hydrogeology, overall and indiscriminate grouting reinforcement is carried out. There are problems such as unclear geological information, unclear reinforcement area, inadequate control of the reinforcement process, and the reinforcement construction method is not adapted to the actual geological conditions. As a result, the reinforcement is not targeted, the reinforcement effect is poor, the reinforcement construction is cumbersome and the construction cost is high. In the later stage, there are still problems such as leakage and large deformation of surrounding rock. Summary of the invention

[0005] The purpose of the present invention is to provide a high-pressure water-rich section surrounding rock grouting construction method, which carries out reasonable zoning reinforcement on the basis of accurately grasping the geological conditions, and performs dynamic grouting construction, which can effectively solve the problems of large deformation of surrounding rock and sudden water gushing when the tunnel passes through the high-pressure water-rich fault fracture zone.

[0006] The technical solution of the present invention is:

[0007] A high-pressure water-rich section surrounding rock grouting construction method comprises the following steps:

[0008] Conduct advanced geological forecast of surrounding rocks and describe geological conditions;

[0009] Drilling a deep hole at the tunnel face to obtain a core sample, and discharging part of the groundwater through the deep hole;

[0010] The core samples are subjected to physical and mechanical tests to obtain the physical, mechanical and permeability properties of the rock mass. Combined with the results of advanced geological forecasting and geological condition description and theoretical analysis, the surrounding rock grade is refined and corrected, and the surrounding rock is divided into loosening and destruction zones, elastic-plastic deformation zones and elastic deformation micro-disturbance zones, and the grouting area is locked;

[0011] The locked grouting area is subjected to advanced deep hole dynamic grouting, including forming a grouting anti-seepage wall between the elastic deformation micro-disturbance zone and the elastic-plastic deformation zone, forming a grouting reinforcement zone in the loose damage zone, and forming a grouting reinforcement zone between the grouting reinforcement zone and the grouting anti-seepage wall.

[0012] Preferably, as a further improvement of the present invention, the advanced geological prediction of the surrounding rock includes exploring the spatial position, scale and volume, pressure and recharge status of the water-bearing body in the surrounding rock.

[0013] Preferably, as a further improvement of the present invention, the technical means used for advanced geological prediction of surrounding rocks include long- and short-range comprehensive detection combining geological radar, transient electromagnetic and seismic waves.

[0014] Preferably, as a further improvement of the present invention, the description of geological conditions includes description of surrounding rock lithology, surrounding rock seepage, joint and fissure development and geological structure trend.

[0015] Preferably, as a further improvement of the present invention, before drilling the advance deep hole at the face, a back-pressure retaining wall is backfilled and constructed from the tunnel arch foot to the arch line to prevent the collapse of the surrounding rock side and the face arch foot, thereby improving the stability of the surrounding rock.

[0016] Preferably, as a further improvement of the present invention, when the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, a pressure sensing element is arranged at the front end of the grouting pipe to detect the soil pressure and pore water pressure, and the grouting pressure and grouting amount are adjusted in real time according to the pressure, so that the grouting pressure is greater than the sum of the water and soil pressures, and the slurry is ensured to diffuse to the formation range with a radius of 30cm-50cm around the hole.

[0017] Preferably, as a further improvement of the present invention, when the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, the grouting process parameters are adapted to the geological conditions. If it is a broken loose stratum with less water, medium-low pressure single-liquid grouting with a grouting pressure of 0.58MPa-0.8MPa is adopted. If it is a fractured rock with a larger water volume, high-pressure double-liquid grouting with a pressure of 0.88MPa-1.2MPa is adopted to achieve targeted construction.

[0018] Preferably, as a further improvement of the present invention, when the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, the grouting sequence follows the principle of upstream first and downstream later, top first and bottom later, water holes first and non-water holes later. The first grouting anti-seepage wall is first formed in the outer circle to cut off the water flow, so that the water volume in the surrounding strata is effectively controlled. Then, grouting is performed on the loose and damaged area of ​​the surrounding rock to form a reinforcement area to limit the deformation of the surrounding rock. Finally, grouting holes are formed at the anti-seepage wall according to the design requirements, and slurry is sprayed from the bottom of the hole. The slurry is sprayed and rotated backward while spraying to form a grouting reinforcement area between the anti-seepage wall and the grouting reinforcement area.

[0019] Preferably, as a further improvement of the present invention, after grouting, the stability of the tunnel is evaluated by monitoring the tunnel water leakage, the vault settlement, the peripheral convergence and the elastic wave velocity parameter test results of the surrounding rock.

[0020] Preferably, as a further improvement of the present invention, the grouting effect is tested by combining coring with acoustic wave detection 4-8 hours after grouting. If the quality does not meet the requirements, secondary compensatory grouting is performed.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention is highly targeted and carries out reasonable zoning reinforcement based on an accurate grasp of the geological conditions. It performs information-based dynamic grouting construction by monitoring the internal water pressure and surrounding rock deformation. The project quality is guaranteed and the reinforcement effect is good. It can effectively solve the problems of large deformation of the surrounding rock and sudden water gushing when the tunnel passes through a high-pressure, water-rich fault fracture zone, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the partition grouting section of the present invention;

[0024] Figure 2 It is a schematic diagram of the grouting construction sequence of the present invention. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1 to Figure 2 , a specific embodiment of the present invention is described in detail. In the description of the invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the invention, unless otherwise specified, "multiple" means two or more.

[0026] Example

[0027] like Figure 1 to Figure 2 As shown, an embodiment of the present invention provides a high-pressure water-rich section surrounding rock grouting construction method, comprising the following steps:

[0028] 1) Advance prediction and understanding of geology. Through the long- and short-distance comprehensive detection technology combining geological radar, transient electromagnetic (this method is sensitive to water) and seismic waves, the spatial position, scale and volume, pressure and recharge status of the surrounding rock water body are explored, and the surrounding rock lithology, surrounding rock leakage, joint and fissure development and geological structure trend are described to do a good job in the early geological prediction.

[0029] 2) Arch foot back pressure, drilling pressure relief. Backfill and construct a 2m long, 2m thick and 1.5m high back pressure retaining wall (the specific size can be determined in combination with the actual situation of the tunnel) from the arch foot to the arch line to prevent the collapse of the surrounding rock side and the arch foot of the tunnel face and improve the stability of the surrounding rock. In combination with the engineering geological conditions, a hydraulic rotary drill is used to drill an advance deep hole on the tunnel face. The hole is both a pressure relief hole, a geological detection hole and a grouting hole. Through the advance deep hole, a limited amount of groundwater is discharged to achieve drainage pressure reduction and a relative balance state, which creates conditions for subsequent grouting construction, maintains the ecological balance of groundwater, and reduces the impact of construction on the environment.

[0030] 3) Refine the classification and lock the area. Through advance drilling of deep holes, we can further understand the engineering geology and hydrogeology ahead, and conduct strength, permeability, particle size and wave velocity tests on the core samples to obtain the physical, mechanical and permeability properties of the rock and soil. Combined with the advance detection results of groundwater, the results of geological condition description and theoretical analysis in step 1), the surrounding rock level is refined and corrected, and the surrounding rock is divided into loose damage zone, elastic-plastic deformation zone and elastic deformation micro-disturbance zone, and the grouting reinforcement area is locked to provide basic data for subsequent construction process control.

[0031] 4) Dynamic grouting and zoning control. For advanced deep hole grouting, a pressure sensor is installed at the front end of the grouting pipe to detect soil pressure and pore water pressure. The grouting pressure and grouting volume are adjusted in real time according to the pressure. The grouting pressure should not be less than the sum of the water and soil pressures, and the slurry should be spread to the stratum with a radius of 30cm-50cm around the hole to achieve information construction. The grouting process parameters should be adapted to the geological conditions. If it is a broken and loose stratum with less water, a medium-low pressure single-liquid grouting pressure of 0.5MPa-0.8MPa is used. If it is a fractured rock with a large amount of water, a high-pressure double-liquid grouting pressure of 0.8MPa-1.2MPa should be used to achieve targeted construction.

[0032] The grouting sequence should follow the principle of upstream first, downstream second, top first, bottom second, water holes first, and no water holes second. First, form the first grouting anti-seepage wall in the outer circle to cut off the water flow, so that the water volume in the surrounding strata can be effectively controlled, thereby achieving the purpose of anti-seepage and plugging leakage, protecting the ecological environment, and creating water-free construction conditions for subsequent construction; then, grouting is performed on the loose and damaged areas of the surrounding rock to form a reinforcement area to limit the deformation of the surrounding rock; finally, grouting holes are formed at the anti-seepage wall according to the design requirements, and slurry is sprayed from the bottom of the hole, while spraying and rotating backward, forming a grouting reinforcement area between the anti-seepage wall and the grouting reinforcement area. By optimizing the grouting sequence and controlling the construction by zoning, a good comprehensive effect of grouting water blocking and deformation control can be achieved.

[0033] 5) Process control, interlocking. Reasonably control the parameters such as grouting pressure, grouting step, grouting sequence and grouting angle, first construct area 1→6, then construct area Ⅰ→Ⅴ, so that the grouting in the same circle is interlocked, leaving no blind spots, and ensuring the overall grouting effect. During the grouting process, according to the pressure monitored by the pressure sensor element at the front end of the grouting pipe, the grouting pressure is adjusted dynamically in real time to ensure the effectiveness of grouting.

[0034] 6) Quality inspection and effect evaluation. Grouting in the crushed section of the high-pressure fault should not only stop water and prevent outbursts, but also strengthen the surrounding rock as a whole and control the deformation of the surrounding rock. After grouting, the stability of the tunnel is evaluated by testing the parameters such as tunnel leakage monitoring, arch sinking, peripheral convergence and elastic wave velocity of the surrounding rock. After 4-8 hours of grouting, the grouting effect is tested by combining drilling and coring and acoustic detection. If the quality does not meet the requirements, secondary compensatory grouting should be carried out.

[0035] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A high-pressure water-rich section surrounding rock grouting construction method, characterized in that: The following steps are involved: Conduct advanced geological forecast of surrounding rocks and describe geological conditions; Drilling a deep hole at the tunnel face to obtain a core sample, and discharging part of the groundwater through the deep hole; The core samples are subjected to physical and mechanical tests to obtain the physical, mechanical and permeability properties of the rock mass. Combined with the results of advanced geological forecasting and geological condition description and theoretical analysis, the surrounding rock grade is refined and corrected, and the surrounding rock is divided into loosening and destruction zones, elastic-plastic deformation zones and elastic deformation micro-disturbance zones, and the grouting area is locked; The locked grouting area is subjected to advanced deep hole dynamic grouting, including forming a grouting anti-seepage wall between the elastic deformation micro-disturbance zone and the elastic-plastic deformation zone, forming a grouting reinforcement zone in the loose damage zone, and forming a grouting reinforcement zone between the grouting reinforcement zone and the grouting anti-seepage wall.

2. The high-pressure water-rich section surrounding rock grouting construction method according to claim 1 is characterized in that: The advanced geological prediction of the surrounding rock includes exploring the spatial location, scale and volume, pressure and recharge status of the surrounding rock water-bearing body.

3. The high-pressure water-rich section surrounding rock grouting construction method according to claim 2 is characterized in that: The technical means used for advanced geological prediction of surrounding rocks include long- and short-distance comprehensive detection combining geological radar, transient electromagnetic and seismic waves.

4. The high-pressure water-rich section surrounding rock grouting construction method according to claim 1 is characterized in that: The description of geological conditions includes description of surrounding rock lithology, surrounding rock seepage, development of joints and fissures, and direction of geological structures.

5. The high-pressure water-rich section surrounding rock grouting construction method according to claim 1 is characterized in that: Before drilling the advance deep hole at the tunnel face, a backfill and construction counter-pressure retaining wall is constructed from the tunnel arch foot to the arch line to prevent the surrounding rock side and the tunnel face arch foot from collapsing and improve the stability of the surrounding rock.

6. The high-pressure water-rich section surrounding rock grouting construction method according to claim 1 is characterized in that: When the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, a pressure sensing element is arranged at the front end of the grouting pipe to detect the soil pressure and pore water pressure, and the grouting pressure and grouting amount are adjusted in real time according to the pressure, so that the grouting pressure is greater than the sum of the water and soil pressures, and the slurry is ensured to diffuse to the formation range with a radius of 30cm-50cm around the hole.

7. The high-pressure water-rich section surrounding rock grouting construction method according to claim 6 is characterized in that: When the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, the grouting process parameters are adapted to the geological conditions. If it is a broken loose stratum with less water, medium-low pressure single-liquid grouting with a grouting pressure of 0.58MPa-0.8MPa is adopted. If it is a fractured rock with a larger water volume, high-pressure double-liquid grouting with a grouting pressure of 0.88MPa-1.2MPa is adopted to achieve targeted construction.

8. The high-pressure water-rich section surrounding rock grouting construction method according to claim 7 is characterized in that: When the locked grouting reinforcement area is subjected to advanced deep hole dynamic grouting, the grouting sequence follows the principle of upstream first and downstream later, top first and bottom later, water holes first and non-water holes later. The first grouting anti-seepage wall is formed in the outer circle first to cut off the water flow, so that the water volume in the surrounding strata is effectively controlled. Then, grouting is performed on the loose and damaged area of ​​the surrounding rock to form a reinforcement area to limit the deformation of the surrounding rock. Finally, grouting holes are formed at the anti-seepage wall according to the design requirements, and slurry is sprayed from the bottom of the hole. The slurry is sprayed and rotated backward while being sprayed to form a grouting reinforcement area between the anti-seepage wall and the grouting reinforcement area.

9. The high-pressure water-rich section surrounding rock grouting construction method according to claim 8 is characterized in that: After grouting, the stability of the tunnel was evaluated by monitoring the tunnel water leakage, vault settlement, peripheral convergence and surrounding rock elastic wave velocity parameter test results.

10. The high-pressure water-rich section surrounding rock grouting construction method according to claim 9, characterized in that: 4-8 hours after grouting, the grouting effect is tested by combining core drilling and ultrasonic detection. If the quality does not meet the requirements, secondary compensatory grouting is carried out.

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