Shield construction method for penetrating through deep miscellaneous fill
By using grouting reinforcement outside the tunnel and injecting thixotropic mud outside the shield machine, the problem of foam loss in deep and miscellaneous soil is solved, the soil stability and construction safety are improved, and the stability of shield excavation is achieved. and efficiency.
Patent Information
- Application Number
- CN202411376193.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2024-12-10
AI Technical Summary
During shield construction, when passing through deep and thick soil fill, foam is very likely to be lost through the void, making it difficult to maintain the soil pressure value, resulting in ground settlement and collapse, affecting construction safety and quality.
The deep-hole grouting reinforcement method is used to inject cement or cement-water glass double slurry within the outer contour line of the tunnel to improve soil stability, and thixotropic mud is injected outside the shield machine to reduce friction force to reduce soil disturbance.
It effectively improves the stability of miscellaneous fill, avoids collapse and ground settlement, ensures the safety and quality of construction, and realizes the stability and efficiency of shield excavation.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of shield construction, and more specifically to a shield construction method for penetrating thick mixed fill soil. Background Art
[0002] In recent years, with the rapid development of my country's economy and the acceleration of urbanization, the construction of urban rail transit and urban underground rail transit has also been deeply promoted. The subway is a rail transit built on a fully enclosed line underground in the city, which is operated by electricity as a traction power. When it is necessary to bypass the ground buildings or the construction depth is deep during the construction of the subway tunnel, the construction is carried out by the method of dark tunneling. However, if the foundation soil of the construction site includes miscellaneous fill soil with thick soil, uneven soil, messy composition, loose structure, and poor engineering performance, the miscellaneous fill soil layer has messy composition, large voids, and no self-stabilizing ability. During the shield excavation process, the foam used for slag improvement is very easy to lose through the voids in the miscellaneous fill soil layer, making it difficult to maintain the predetermined earth pressure value, and unable to ensure the stability of the face, which is easy to cause the ground settlement to increase. In severe cases, collapse will occur during the earth excavation process, causing adverse effects.
[0003] Therefore, there is an urgent need for a shield construction method that penetrates deep mixed fill. Summary of the invention
[0004] The technical problem to be solved by the present invention is to provide a shield construction method for penetrating deep mixed fill soil, so as to solve the problems in the background technology.
[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.
[0006] A shield construction method for crossing thick mixed fill soil, specifically comprising the following steps:
[0007] S1. Preparation before construction: Check the pipelines, including the direction, diameter, material, purpose, valve position, etc., and register them clearly. The surveyor will mark the crossing position of the pipeline and set up warning signs to facilitate hole position adjustment during grouting construction to avoid the pipeline;
[0008] S2. Determine the grouting scope: determine whether the miscellaneous fill layer is outside the tunnel structure or within the tunnel structure; if the miscellaneous fill layer is outside the tunnel structure, cement grout is injected to reinforce the left and right sides outside the tunnel outline and above the tunnel vault; if the miscellaneous fill layer is within the tunnel structure, cement grout is injected to reinforce the tunnel range and the left and right sides outside the tunnel outline and above the vault;
[0009] S3. Grouting construction:
[0010] S31, ground leveling: restore the exploration trenches and trenches, and maintain the ground elevation;
[0011] S32, Construction layout: Positioning and layout, contact the surveying team to confirm the position coordinates, and mark the hole positions;
[0012] S33, determine the hole position: according to the reinforcement range and the tunnel outer contour line measurement data of step S2, make positioning marks on the ground; mark the hole position in advance, align the hole position, select the angle, and fix the lead hole drilling machine;
[0013] S34, drilling rig in place: the drilling rig is in place at the designated position and the verticality of the drill rod is adjusted;
[0014] S35. Drilling: When drilling the first hole, operate slowly to understand the influence of the formation on the drilling rig and determine the drilling parameters under the formation conditions; closely observe the overflow and water discharge. If a large amount of overflow and water discharge occurs, stop drilling immediately and analyze the cause before drilling again; check each section after drilling and correct the deviation in time;
[0015] S36, Draw back the drill rod: strictly control the draw back amplitude, each step should not be greater than 15-20cm, draw back at a constant speed, and pay attention to the changes in grouting parameters;
[0016] S37, Grouting reinforcement: Use accurate measuring tools to mix the slurry according to the designed formula; then strictly control the grouting pressure for grouting reinforcement, and pay close attention to the grouting volume;
[0017] S4. Shield tunneling: Inject thixotropic mud outside the shield machine body to reduce the friction of the shield machine shell to reduce the disturbance to the surrounding soil, and start the tunneling of the shield machine.
[0018] To further optimize the technical solution, in step S3, the reinforcement thickness on the left and right sides outside the tunnel outline is at least 300 mm greater than the tunnel radius, and the reinforcement thickness on the arch is at least 300 mm greater than the tunnel radius.
[0019] To further optimize the technical solution, the type of slurry used for injecting cement slurry in step S3 is cement slurry or cement-water glass double liquid slurry.
[0020] The technical solution is further optimized, wherein the cement in the cement slurry is ordinary Portland cement with a P·O 42.5; the water glass modulus is 2.4-3.5, and the Baume degree Be is 30-40°; the water-cement mass ratio of the cement slurry is 1:1; the double liquid slurry ratio is: the volume ratio of the cement slurry to the water glass solution is 1:1, and the slurry viscosity is 80s-90s.
[0021] To further optimize the technical solution, in step S3, the grouting construction is carried out from the outside to the inside, first around the tunnel and then in the middle, with alternate grouting of alternate holes, and the outermost row is filled with double-liquid slurry. After the double-liquid slurry solidifies, cement slurry is injected again.
[0022] To further optimize the technical solution, when fixing the hole drill in step S33, the hole position deviation is required to be 0 to +3 cm, and the incident angle deviation is required to be no greater than 1°.
[0023] To further optimize the technical solution, during the grouting construction in step S3, the tunnel structure construction ground is reinforced in sections; during each reinforcement, lateral reinforcement is carried out in the order of first the two sides and then the middle, and temporary fencing is used for closure before each reinforcement; after the first section is constructed, the site is cleaned and the fencing is removed, and then the second section of the fencing is closed, and the ground reinforcement is carried out, and the process is carried out in sequence.
[0024] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.
[0025] The present invention provides a shield construction method for penetrating deep mixed fill. For the treatment of mixed fill, ground deep hole grouting reinforcement measures are adopted to reinforce the mixed fill. The method has good effect, strong injectability, stable heading face and fast excavation progress, and avoids the problems of inability to inject the small-sized guiding tube, difficulty in grouting and easy collapse of the heading face caused by advance reinforcement of the small-sized guiding tube. DETAILED DESCRIPTION
[0026] The present invention will be further described in detail below with reference to specific embodiments.
[0027] A shield construction method for crossing thick mixed fill soil, specifically comprising the following steps:
[0028] S1. Preparation before construction: Check the pipelines, including the direction, diameter, material, purpose, valve position, etc., and register them clearly. The surveyor will mark the location where the pipeline crosses and set up warning signs to facilitate hole adjustment during grouting construction to avoid the pipeline. When locating the grouting holes, avoid the existing pipelines and ensure that no grouting positioning holes are arranged within 3m of the pipeline to ensure the safety of the pipeline.
[0029] S2. Determine the scope of grouting: Determine whether the miscellaneous fill soil layer is outside the tunnel structure or within the tunnel structure. If the miscellaneous fill soil layer is outside the tunnel structure, cement grouting is performed on the left and right sides outside the tunnel outline and above the tunnel vault for reinforcement; if the miscellaneous fill soil layer is within the tunnel structure, cement grouting is performed on the tunnel range and the left and right sides outside the tunnel outline and above the vault for reinforcement. The reinforcement thickness on the left and right sides outside the tunnel outline is at least 300mm greater than the tunnel radius, and the reinforcement thickness on the vault is at least 300mm greater than the tunnel radius.
[0030] S3. Grouting construction:
[0031] During the grouting construction process, the tunnel structure construction ground is reinforced in sections; each time reinforcement is carried out, the two sides are reinforced first, and then the middle, and temporary fences are used to close it before each reinforcement. After the first section is completed, the site is cleaned and the fences are removed. Then the second section of the fence is closed, and the ground reinforcement is carried out, and the process moves forward in sequence. After the grouting construction is completed, the road surface is restored in an orderly manner and the fences are removed. The details are as follows:
[0032] S31. Ground leveling: Restore the exploration trenches and trenches and maintain the ground elevation.
[0033] S32, construction layout: positioning and layout, contact the surveying team to confirm the position coordinates, and mark the hole positions.
[0034] S33, determine the hole position: according to the reinforcement range and tunnel outer contour measurement data of step S2, make positioning marks on the ground; mark the hole position in advance, align the hole position, select the angle, and fix the lead hole drill. When fixing the lead hole drill, the hole position deviation is required to be 0~+3cm, and the incident angle deviation is not more than 1°
[0035] S34, Drilling rig in place: The drilling rig is placed in the designated position and the verticality of the drill rod is adjusted.
[0036] S35. Drilling: When constructing the first hole, operate slowly to understand the impact of the formation on the drilling rig in order to determine the drilling parameters under the formation conditions; closely observe the overflow and water discharge. When a large amount of overflow and water discharge occurs, stop drilling immediately and analyze the cause before proceeding with construction; inspect each section after drilling and correct the deviation in a timely manner.
[0037] S36. Pull back the drill rod: strictly control the withdrawal amplitude, each step should not exceed 15 to 20 cm, withdraw at a uniform speed, and pay attention to changes in grouting parameters.
[0038] S37, Grouting reinforcement: Use accurate measuring tools and mix slurry according to the designed formula. Strictly control the grouting pressure for grouting reinforcement, and pay close attention to the grouting volume. During the grouting construction, start from the outside to the inside, first around the tunnel and then in the middle, alternately grouting every other hole, and inject double liquid slurry in the outermost row. After the double liquid slurry solidifies, inject cement slurry again.
[0039] The slurry type used for cement grouting is cement slurry or cement-water glass double liquid slurry. The cement in the cement slurry is P·O42.5 ordinary silicate cement; the water glass modulus is 2.4-3.5, and the Baume degree is Be30-40°; the water-cement mass ratio of the cement slurry is 1:1; the double liquid slurry ratio is: the volume ratio of cement slurry to water glass solution is 1:1, and the slurry viscosity is 80s-90s.
[0040] During the reinforcement process, strengthen ground inspections and control the grouting pressure to prevent excessive grouting pressure from causing ground uplift and damaging existing pipelines.
[0041] S4. Shield tunneling: Inject thixotropic mud outside the shield machine body to reduce the friction of the shield machine shell to reduce the disturbance to the surrounding soil, and start the tunneling of the shield machine.
[0042] The invention is used in a dark excavated tunnel of a certain subway line in a certain place. The tunnel includes a left line and a right line. The tunnel lengths are 442.043m and 460.422m respectively, and the line spacing is 10.15m to 15.57m. The tunnel radius is 2750mm and the tunnel thickness is 350mm.
[0043] According to the detailed survey, supplementary survey reports and on-site excavation of soil, in the construction area, the backfill time of miscellaneous fill is short, the backfill composition is complex, and there are characteristics such as uneven properties, large variations in thickness and density, obvious settlement and deformation due to poor rolling treatment, loose structure, low strength, large pores and uneven permeability, and low bearing capacity. The properties of the fill vary greatly and are generally loose. The tunnel surrounding rock is classified as Grade VI, the surrounding rock cannot be self-stabilized, and collapse is very likely to occur during earth excavation.
[0044] During the construction of the present invention, the specific steps are as follows:
[0045] S1. Preparation before construction: Check the pipelines, including the direction, diameter, material, purpose, valve position, etc., and register them clearly. The surveyor will mark the location where the pipeline crosses and set up warning signs to facilitate hole adjustment during grouting construction to avoid the pipeline. When locating the grouting holes, avoid the existing pipelines and ensure that no grouting positioning holes are arranged within 3m of the pipeline to ensure the safety of the pipeline.
[0046] S2. Determine the scope of grouting: Determine whether the miscellaneous fill layer is outside the tunnel structure or within the tunnel structure. If the miscellaneous fill layer is outside the tunnel structure, cement grouting is performed on the left and right sides outside the tunnel outline and above the tunnel vault for reinforcement; if the miscellaneous fill layer is within the tunnel structure, cement grouting is performed on the tunnel range and the left and right sides outside the tunnel outline and the 3.0m range above the vault for reinforcement. The reinforcement thickness on the left and right sides outside the tunnel outline is at least 300mm greater than the tunnel radius, and the reinforcement thickness on the vault is at least 300mm greater than the tunnel radius.
[0047] S3. Grouting construction:
[0048] During the grouting construction process, the tunnel structure construction ground is reinforced in sections; each reinforcement is 20m long and 12.78m wide. During each reinforcement, the lateral reinforcement is carried out in the order of first the two sides and then the middle. Before each reinforcement, a temporary fence is used for closure, and the fence range is 20m×3.5m. After the first section is constructed, the site is cleaned and the fence is removed. Then the second section of the fence is closed, and the ground reinforcement is carried out, and the process is carried out in sequence. After the grouting construction is completed, the road surface is restored in an orderly manner and the fence is removed. The details are as follows:
[0049] S31. Ground leveling: Restore the exploration trenches and trenches and maintain the ground elevation.
[0050] S32, construction layout: positioning and layout, contact the surveying team to confirm the position coordinates, and mark the hole positions.
[0051] S33, determine the hole position: according to the reinforcement range and tunnel outer contour measurement data of step S2, make positioning marks on the ground; mark the hole position in advance, align the hole position, select the angle, and fix the lead hole drill. When fixing the lead hole drill, the hole position deviation is required to be 0~+3cm, and the incident angle deviation is not more than 1°
[0052] S34, Drilling rig in place: The drilling rig is placed in the designated position and the verticality of the drill rod is adjusted.
[0053] S35. Drilling: When constructing the first hole, operate slowly to understand the impact of the formation on the drilling rig in order to determine the drilling parameters under the formation conditions; closely observe the overflow and water discharge. When a large amount of overflow and water discharge occurs, stop drilling immediately and analyze the cause before proceeding with construction; inspect each section after drilling and correct the deviation in a timely manner.
[0054] S36. Pull back the drill rod: strictly control the withdrawal amplitude, each step should not exceed 15 to 20 cm, withdraw at a uniform speed, and pay attention to changes in grouting parameters.
[0055] S37, grouting reinforcement: Use accurate measuring tools and mix slurry according to the designed formula. Strictly control the grouting pressure for grouting reinforcement, and pay close attention to the grouting volume. During the grouting construction, start from the outside to the inside, first around the tunnel and then in the middle, alternately grouting every other hole, and inject double liquid slurry in the outermost row. After the double liquid slurry solidifies, inject cement slurry again. The diameter of the grouting hole is 50mm, the spacing is 1.5m*1.5m, and it is arranged in a plum blossom shape. The grouting pressure is 0.2~0.3Mpa, and the soil porosity is 0.55. The unconfined compressive strength of the soil after reinforcement is not less than 0.3Mpa.
[0056] The slurry type used for cement grouting is cement slurry or cement-water glass double liquid slurry. The cement in the cement slurry is P·O42.5 ordinary silicate cement; the water glass modulus is 2.4-3.5, and the Baume degree is Be30-40°; the water-cement mass ratio of the cement slurry is 1:1; the double liquid slurry ratio is: the volume ratio of cement slurry to water glass solution is 1:1, and the slurry viscosity is 80s-90s.
[0057] During the reinforcement process, strengthen ground inspections and control the grouting pressure to prevent excessive grouting pressure from causing ground uplift and damaging existing pipelines.
[0058] Inspection holes were set up to check quality and take cores. The grouting consolidation quality and compressive strength were determined by visual inspection. The consolidation strength was greater than 0.3Mpa.
[0059] After the grouting construction is completed, the road surface is restored in an orderly manner, the fence is removed, and 4cm of asphalt is laid. The paving area is 600 square meters, 200m long and 3m wide. After the fence is removed, the anchor nails that fix the fence are cut and inspected by a dedicated person. After the self-inspection is completed, the traffic control department will conduct acceptance. Only after the acceptance is qualified can the road surface be restored to ensure that the flatness of the road surface does not affect the passage of vehicles.
[0060] S4. Shield tunneling: Inject thixotropic mud outside the shield machine body to reduce the friction of the shield machine shell to reduce the disturbance to the surrounding soil, and start the tunneling of the shield machine.
[0061] Through the implementation and detection of the above embodiments, it is concluded that the slurry veins in the miscellaneous fill area of the present invention are obvious, the slurry is easy to accumulate into blocks, and the hardness is relatively large, and it must be broken with a pneumatic pick. The tunnel face is very stable, and no collapse occurs in the tunnel face area. The ground settlement is characterized by first uplift and then settlement, and tends to be stable, with the maximum uplift reaching 1.88cm and the maximum settlement being 2.12cm.
Claims
1. A shield construction method for crossing thick mixed fill, characterized in that: The specific steps include: S1. Preparation before construction: Check the pipelines, including the direction, diameter, material, purpose, valve position, etc., and register them clearly. The surveyor will mark the crossing position of the pipeline and set up warning signs to facilitate hole position adjustment during grouting construction to avoid the pipeline; S2. Determine the grouting scope: determine whether the miscellaneous fill layer is outside the tunnel structure or within the tunnel structure; if the miscellaneous fill layer is outside the tunnel structure, cement grout is injected to reinforce the left and right sides outside the tunnel outline and above the tunnel vault; if the miscellaneous fill layer is within the tunnel structure, cement grout is injected to reinforce the tunnel range and the left and right sides outside the tunnel outline and above the vault; S3. Grouting construction: S31, ground leveling: restore the exploration trenches and trenches, and maintain the ground elevation; S32, Construction layout: Positioning and layout, contact the surveying team to confirm the position coordinates, and mark the hole positions; S33, determine the hole position: according to the reinforcement range and the tunnel outer contour line measurement data of step S2, make positioning marks on the ground; mark the hole position in advance, align the hole position, select the angle, and fix the lead hole drilling machine; S34, drilling rig in place: the drilling rig is in place at the designated position and the verticality of the drill rod is adjusted; S35. Drilling: When drilling the first hole, operate slowly to understand the influence of the formation on the drilling rig and determine the drilling parameters under the formation conditions; closely observe the overflow and water discharge. If a large amount of overflow and water discharge occurs, stop drilling immediately and analyze the cause before drilling again; check each section after drilling and correct the deviation in time; S36, Draw back the drill rod: strictly control the draw back amplitude, each step should not be greater than 15-20cm, draw back at a constant speed, and pay attention to the changes in grouting parameters; S37, Grouting reinforcement: Use accurate measuring tools to mix the slurry according to the designed formula; Then, the grouting pressure is strictly controlled for grouting reinforcement, and the grouting volume is closely monitored at the same time; S4. Shield tunneling: Inject thixotropic mud outside the shield machine body to reduce the friction of the shield machine shell to reduce the disturbance to the surrounding soil, and start the tunneling of the shield machine.
2. A shield construction method for crossing thick miscellaneous fill according to claim 1, characterized in that: In step S3, the reinforcement thickness on the left and right sides outside the tunnel outline is at least 300 mm greater than the tunnel radius, and the reinforcement thickness on the arch is at least 300 mm greater than the tunnel radius.
3. A shield construction method for crossing thick miscellaneous fill according to claim 1, characterized in that: The type of slurry used for injecting cement slurry in step S3 is cement slurry or cement-water glass double liquid slurry.
4. A shield construction method for crossing thick miscellaneous fill according to claim 3, characterized in that: The cement in the cement slurry is ordinary silicate cement with a P·O 42.5; the water glass modulus is 2.4-3.5, and the Baume degree Be is 30-40°; the water-cement mass ratio of the cement slurry is 1:1; the double liquid slurry ratio is: the volume ratio of the cement slurry to the water glass solution is 1:1, and the slurry viscosity is 80s-90s.
5. The shield construction method for crossing thick miscellaneous fill according to claim 1, characterized in that: In step S3, the grouting is carried out from the outside to the inside, first around the tunnel and then in the middle, and alternately grouting is carried out in alternate holes. The outermost row is filled with double-liquid slurry. After the double-liquid slurry solidifies, cement slurry is injected again.
6. A shield construction method for crossing thick miscellaneous fill according to claim 1, characterized in that: When fixing the hole drill in step S33, the hole position deviation is required to be 0 to +3 cm, and the incident angle deviation is required to be no greater than 1°.
7. The shield construction method for penetrating deep mixed fill according to claim 1, characterized in that: During the grouting construction in step S3, the tunnel structure construction ground is reinforced in sections; each time reinforcement is carried out, lateral reinforcement is carried out in the order of first the two sides and then the middle, and temporary enclosures are used for closure before each reinforcement; after the first section is constructed, the site is cleaned, the enclosures are removed, and then the second section of the enclosure is closed, and the stratum is reinforced, and the process is carried out in sequence.