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CN-121993227-A - Tunnel long-distance high-pressure advanced grouting construction method

CN121993227ACN 121993227 ACN121993227 ACN 121993227ACN-121993227-A

Abstract

The invention discloses a tunnel long-distance high-pressure advanced grouting construction method, and aims to solve the problems of short reinforcement length, long construction period, multiple holes, high slurry stringing risk and poor pressurized hole water blocking effect of the conventional advanced grouting technology. The method comprises five steps of stable rock formation, hole site optimization design, segmented drilling and hole site sealing, high-pressure grouting construction and quality inspection after grouting, wherein the hole site is optimized based on the effective diffusion radius of 3.5m slurry, the hole site is contracted by 1.0-1.3 m, the hole bottom is expanded by 1.0-1.5 m, the total length of single-cycle grouting reaches 100m, a bag-type sealing device is adopted to realize rapid high-pressure sealing of the hole site, a sealing ring resisting the pressure of more than or equal to 10MPa is formed within 12 hours, and a two-sequence hole jumping process is implemented during grouting, so that the pressure and the injection rate are dynamically matched and controlled. The number of grouting holes is greatly reduced, the construction period is shortened, the high-pressure grouting is adapted to a pressurized water stratum, the water blocking and reinforcing effects are obvious, the process flexibility is high, the risk of engineering accidents can be effectively avoided, and the method is suitable for tunnel construction with large burial depth, high water enrichment and complex geological conditions.

Inventors

  • DENG FUYANG
  • YANG MIN
  • LI JIAHAO
  • LI QINGPENG
  • JIANG XINGYI
  • WANG YIWEN
  • ZHANG JIANWEI
  • WANG YU
  • JIANG ZHENGWEI
  • YUAN QING
  • CHEN XIAOTIAN
  • HUANG JIHUA
  • DONG SHAOZHENG
  • YUAN YE

Assignees

  • 中国葛洲坝集团三峡建设工程有限公司
  • 中国南水北调集团江汉水网建设开发有限公司

Dates

Publication Date
20260508
Application Date
20260116

Claims (10)

  1. 1. The tunnel long-distance high-pressure advanced grouting construction method is characterized by comprising the following steps of: Step one, forming a stable rock disk, and reinforcing a face and surrounding rocks at the rear of a hole section to be grouted to form a stable rock disk structure with the length not less than 5 m; Secondly, optimally designing hole sites, optimally designing the hole sites of grouting holes along a tunnel excavation contour line based on the effective diffusion radius of high-pressure grouting slurry, enabling the hole sites to be positioned on a tunnel face and shrink inwards of the contour line, and enabling the hole bottoms to extend out of the contour line; Step three, sectionally drilling and hole opening sealing, drilling by adopting a grading aperture, realizing rapid high-pressure sealing of the hole opening of the drill hole by using a grouting device aiming at each grouting section, and dividing the total length of single-cycle grouting into a plurality of grouting sections; Step four, high-pressure grouting construction, adopting an in-hole circulation method or pure pressure grouting, implementing a two-sequence hole jumping process, controlling grouting pressure in a grading manner, dynamically matching the grouting rate, and converting the water-ash proportion of the slurry from thin to thick; And fifthly, after the grouting is finished and the solidification is finished, drilling an inspection hole to carry out a water pressure test, and taking the preset water permeability and the water seepage quantity per unit length as reinforcement qualification judgment standards.
  2. 2. The method of high pressure advanced grouting for long distance in tunnel of claim 1, wherein in the second step, the inward contraction distance of the hole opening to the contour line is 1.0-1.3 m, the outward expansion distance of the hole bottom to the contour line is 1.0-1.5 m, and the effective diffusion radius of slurry is 3.5 m based on grouting pressure.
  3. 3. The tunnel long-distance high-pressure advanced grouting construction method according to claim 1, wherein in the third step, the aperture of an orifice section with a graded aperture is more than or equal to 180mm, the total length of single-cycle grouting is 80 meters or 100 meters, and the single-section length of each grouting section is 20-40 meters.
  4. 4. The tunnel long-distance high-pressure advanced grouting construction method is characterized in that the grouting device comprises an in-hole grouting pipe (1), an in-hole grouting pipe (2), an expandable sealing element and a sealing element inner slurry circulation pipeline, the in-hole grouting pipe (1) and the in-hole grouting pipe (2) are arranged in parallel, the sealing element is sleeved outside orifice sections of the in-hole grouting pipe (1) and the in-hole grouting pipe (2), one end of the sealing element inner slurry circulation pipeline is connected with the sealing element, the other end of the sealing element inner slurry circulation pipeline extends to the outside, and an in-hole grouting ball valve (3) and an in-hole grouting ball valve (4) are respectively connected at ports of the in-hole grouting pipe (1) and the in-hole grouting pipe (2) located outside a hole.
  5. 5. The method of long-distance high-pressure advanced grouting construction for tunnels of claim 4, wherein the slurry injected into the sealing member is cement mortar with a water cement ratio of 1:1 to 0.5:1, and the sealing member forms a high-strength sealing ring resistant to grouting pressure of not less than 10MPa within 12 hours after the slurry is coagulated.
  6. 6. The tunnel long-distance high-pressure advanced grouting construction method of claim 5, wherein the sealing element is a bag (8), the bag (8) is made of industrial filter cloth, the length of the bag (8) is 3.5-4 m, and the bag (8) can be attached to the wall of a corresponding drilling hole after being expanded.
  7. 7. The tunnel long-distance high-pressure advanced grouting construction method of claim 4 is characterized in that the slurry circulation pipeline inside the sealing element comprises a bag grouting pipe (5), a bag grouting return pipe (6) and a bag grouting ball valve (7) connected to the movable end of the bag grouting pipe (5).
  8. 8. The tunnel long-distance high-pressure advanced grouting construction method of claim 4, wherein when grouting the sealing element, grouting is carried out after the sealing element is filled with cement mortar, the grouting pipeline of the sealing element is shielded for 20 minutes, and grouting is carried out after 4 hours of grouting.
  9. 9. The method for long-distance high-pressure advanced grouting construction of a tunnel according to claim 1, wherein in the fourth step, the two-sequence hole-jumping process is that drilled holes are sequentially numbered, odd-numbered holes are implemented first, and after construction of adjacent odd-numbered holes is completed, corresponding even-numbered holes are implemented; The dynamic matching control of the grouting pressure and the injection rate follows the following relation: when the injection rate is more than 200L/min, the control pressure is less than 0.3P; Controlling the pressure to be 0.3P to 0.5P when the injection rate is 200 to 120L/min; controlling the pressure to be 0.5P to 0.8P when the injection rate is 120 to 60L/min; when the injection rate is less than 60L/min, controlling the pressure to be 0.8P to 1.0P; wherein P is the design grouting pressure.
  10. 10. The tunnel long-distance high-pressure advanced grouting construction method is characterized in that in the fourth step, pure cement slurry is adopted for grouting, the slurry water-cement ratio is 2:1, 1:1, 0.7:1 and 0.5:1, the cement ratio of each stage is changed from thin to thick step by step, the grouting amount of each stage is more than or equal to 900L at 15m, more than or equal to 1200L at 20m, more than or equal to 1500L at 25m and more than or equal to 1800L at 30m, the concentration is changed by one stage when the pressure and the flow are not obviously changed, the grouting pressure is kept unchanged, the injection rate is continuously reduced, or the cement ratio is not changed when the injection rate is continuously increased under the condition that the pressure is not changed.

Description

Tunnel long-distance high-pressure advanced grouting construction method Technical Field The invention relates to the technical field of tunnel engineering construction, in particular to a long-distance high-pressure advanced grouting construction method for tunnels. Background In tunnel excavation construction, advanced grouting is a key technology for guaranteeing stability of surrounding rock and blocking groundwater water. The conventional advanced grouting technology has the defects of large buried depth, strong water enrichment, complex geological conditions (such as fracture zones and solution gap development zones), namely, the horizontal reinforcement length is short (usually within 30 m), frequent cyclic construction is needed to prolong the construction period, the number of grouting holes is large (usually more than 60 holes), the sectional order is complex, the grouting phenomenon is very easy to occur, the reinforcement effect is influenced, the grouting pressure is low (4-6 MPa), the water blocking reinforcement effect is poor for the pressurized holes with the hydrostatic pressure of more than 1.2MPa, and the construction time of the grout stopping wall and the grout stopping pad is long (about 10 days), so that the construction progress is further restricted. Disclosure of Invention The invention aims to solve the problems of short reinforcement length, long construction period, multiple holes, high slurry-mixing risk and the like of the conventional advanced grouting technology, and provides a tunnel long-distance high-pressure advanced grouting construction method. In order to solve the technical problems, the technical scheme adopted by the invention is that the tunnel long-distance high-pressure advanced grouting construction method comprises the following steps: Step one, forming a stable rock disk, and reinforcing a face and surrounding rocks at the rear of a hole section to be grouted to form a stable rock disk structure with the length not less than 5 m; Secondly, optimally designing hole sites, optimally designing the hole sites of grouting holes along a tunnel excavation contour line based on the effective diffusion radius of high-pressure grouting slurry, enabling the hole sites to be positioned on a tunnel face and shrink inwards of the contour line, and enabling the hole bottoms to extend out of the contour line; Step three, sectionally drilling and hole opening sealing, drilling by adopting a grading aperture, realizing rapid high-pressure sealing of the hole opening of the drill hole by using a grouting device aiming at each grouting section, and dividing the total length of single-cycle grouting into a plurality of grouting sections; Step four, high-pressure grouting construction, adopting an in-hole circulation method or pure pressure grouting, implementing a two-sequence hole jumping process, controlling grouting pressure in a grading manner, dynamically matching the grouting rate, and converting the water-ash proportion of the slurry from thin to thick; And fifthly, after the grouting is finished and the solidification is finished, drilling an inspection hole to carry out a water pressure test, and taking the preset water permeability and the water seepage quantity per unit length as reinforcement qualification judgment standards. Preferably, in the second step, the inward contraction distance of the orifice to the contour line is 1.0 to 1.3 m, the outward expansion distance of the bottom of the orifice to the contour line is 1.0 to 1.5 m, and the effective diffusion radius of the slurry is determined to be 3.5 m based on the grouting pressure. Preferably, in the third step, the aperture of the orifice section with the grading aperture is more than or equal to 180mm, the total length of the single-cycle grouting is 80 meters or 100 meters, and the single-section length of each grouting section is 20-40 meters. Preferably, the grouting device comprises an in-hole grouting pipe, an expandable sealing element and a sealing element inner slurry circulation pipeline, wherein the in-hole grouting pipe and the in-hole grouting pipe are arranged in parallel, the sealing element is sleeved outside the orifice sections of the in-hole grouting pipe and the in-hole grouting pipe, one end of the sealing element inner slurry circulation pipeline is connected with the sealing element, the other end of the sealing element inner slurry circulation pipeline extends to the outside, and the port positions of the in-hole grouting pipe and the in-hole grouting pipe, which are positioned outside the hole, are respectively connected with an in-hole grouting ball valve and an in-hole grouting ball valve. Preferably, the slurry injected into the sealing member is cement mortar with a water cement ratio of 1:1 to 0.5:1, and the sealing member forms a high-strength sealing ring resistant to grouting pressure of not less than 10MPa within 12 hours after the slurry is coagulated. Preferably, the seali