Shield tunnel construction method and structure for boulder stratum

Abstract

The present application relates to a kind of boulder stratum for shield tunnel construction method, comprising the following steps: exploration shield tunnel along the boulder information of line;In the frequent interval of boulder construction several partition walls;With several partition walls as fulcrum, the boulder of peripheral side is handled;The jacking construction of shield tunnel is carried out.This construction method in the process of construction partition wall, most of boulder is pre-processed, after construction, with partition wall as the basis, the boulder of peripheral side is handled twice.Finally, jacking will partition wall as the fulcrum of shield equipment cutting boulder, solve the problem that boulder follows shield equipment machine head rolls, difficult to cut, improve boulder cutting efficiency;While avoiding the problem of surface subsidence.The method significantly improves the cutting efficiency of shield equipment on boulder as a whole, effectively avoids large-scale surface collapse, and can be reinforced by partition wall to stratum, so as to realize safe, efficient, strong adaptability of boulder stratum shield tunnel construction.

Description

Technical Field

[0001] This invention belongs to the field of shield tunneling technology, and relates to shield tunnels, especially a method and structure for constructing shield tunnels in boulder strata. Background Technology

[0002] In the construction of shield tunnels, it is difficult to overcome the challenges of soft upper layers and hard lower layers, as well as water-rich isolated rock formations. Currently, the following construction methods are mainly used in water-rich isolated rock formations:

[0003] 1. When the tunnel overburden is shallow, boulders encountered during the tunnel boring machine's advance can be removed by creating "windows" on the surface. This method requires an open surface free of buildings or structures and carries high safety risks and a long construction period.

[0004] 2. The method involves removing isolated boulders one by one from the ground surface using rotary drilling rigs or rotary drilling machines. However, this method has the problem of inaccurate positioning of isolated boulders. Removing boulders in large sections can easily cause problems such as hole collapse, cross-holes, and ground subsidence. It is mainly suitable for the pretreatment of a small number of isolated boulders in a localized area. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and structure for constructing shield tunnels in boulder strata with a short construction period and low safety risk.

[0006] To solve the above problems, the technical solution of the present invention is as follows:

[0007] A method for constructing a shield tunnel in boulder strata includes the following steps:

[0008] Explore information on isolated boulders along the shield tunnel route;

[0009] Construct several partition walls in the areas where isolated boulders frequently occur;

[0010] The isolated boulders on the surrounding area were treated using several partition walls as fulcrums;

[0011] The jacking construction of the shield tunnel is carried out.

[0012] In a further embodiment, the exploration of information on isolated boulders along the shield tunnel route specifically includes:

[0013] Information on the distribution of isolated boulders was obtained through borehole exploration;

[0014] Determine the frequent occurrence areas based on distribution information;

[0015] GT scanning of frequent areas is suitable for obtaining information on the number, size, and location of isolated rocks.

[0016] In a further embodiment, several partition walls are constructed at intervals in the areas where boulders frequently occur, specifically including:

[0017] Backfilling is carried out in the area from the top of the partition wall to the ground.

[0018] In a further embodiment, the jacking construction of the shield tunnel specifically includes:

[0019] During the jacking process, the cutterhead is changed after the tunnel boring machine enters each partition wall.

[0020] In a further embodiment, before the cutterhead is changed, the shield machine head is determined to be fully inserted into the partition wall by emptying the shield machine.

[0021] The cutter head of the tunnel boring machine is replaced after it has fully entered the partition wall.

[0022] A shield tunnel structure for boulder strata, constructed using a shield tunnel construction method for boulder strata, comprising:

[0023] Several partition walls are set at intervals along the predetermined route of the shield tunnel, and all of these partition walls are located in areas where boulders frequently occur.

[0024] The protective wall is set up in front of the partition wall along the direction of the tunnel boring machine.

[0025] In a further embodiment, a reinforced area is provided on the front side of the protective wall.

[0026] In a further embodiment, the partition wall uses interlocking piles.

[0027] In a further embodiment, the width of the partition wall is greater than the width of the tunnel boring machine's head, and the height of the partition wall is greater than or equal to two to three times the diameter of the tunnel opening.

[0028] In a further embodiment, the tunneling equipment is a rock tunneling machine.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. This construction method involves setting up several partition walls at intervals in areas prone to boulders. During the construction of these partition walls, most boulders are pre-treated. After construction, the surrounding boulders are further treated using the partition walls as a foundation. Finally, during jacking, the partition walls serve as fulcrums for the tunnel boring machine (TBM) to cut the boulders, solving the problem of boulders rolling with the TBM head and being difficult to cut, thus improving the efficiency of boulder cutting; it also avoids surface subsidence. Overall, this method significantly improves the cutting efficiency of the TBM on boulders, effectively prevents large-scale surface collapse, and reinforces the strata through the partition walls, thereby achieving safe, efficient, and highly adaptable shield tunnel construction in boulder strata.

[0031] 2. This construction method uses the partition wall as the cutter replacement zone for the tunnel boring machine (TBM), providing a closed, stable, and safe environment for opening the tunnel to inspect and replace the cutter in the water-rich sand layer. This allows the TBM to achieve normal pressure opening and cutter replacement without additional dewatering or air pressure assistance, greatly reducing the safety risks of cutter replacement operations.

[0032] 3. The location of the partition wall in this construction method can be flexibly adjusted according to the actual geological conditions and the distribution of boulders on site. It can achieve good stratum reinforcement effect in soft soil, sand layer, pebble layer or composite stratum, and has extremely high stratum adaptability. It can be widely used in shield tunneling under various complex geological conditions.

[0033] 4. This construction method effectively solves the problem of large-scale surface collapse that can easily be caused by tunnel boring machines jacking up isolated rock formations by setting up several partition walls at intervals. The partition walls can limit possible surface deformation or collapse to a local and controllable range, significantly reducing the safety risks of construction to the surface environment and surrounding buildings. Attached Figure Description

[0034] Figure 1 A flowchart of a shield tunnel construction method for boulder strata;

[0035] Figure 2 A side view of a shield tunnel structure used in boulder strata;

[0036] Figure 3 A top view of a shield tunnel structure used in boulder strata;

[0037] Figure 4 This is a schematic diagram of the backfill area for a shield tunnel structure used in boulder strata.

[0038] In the diagram: 1. Protective wall; 2. Dividing wall; 3. Isolated rock; 4. Reinforced area; 5. Backfill area; 6. Shield tunneling equipment; 7. Shield tunnel. Detailed Implementation

[0039] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0040] With economic and social development, shield tunneling is increasingly used in underground water conveyance projects such as urban rail transit, municipal utility tunnels, and water conservancy projects. However, shield tunneling faces challenges in overcoming strata that are soft on top and hard underneath, as well as water-rich isolated boulders. Through extensive research and investigation, the following technical measures are currently being adopted to address shield tunneling encounters with isolated boulder strata:

[0041] 1. Pre-reinforcing the strata in the boulder section using techniques such as MJS piles, high-pressure jet grouting, and double-liquid curtain grouting can reduce surface settlement and collapse caused by over-discharge of earthwork during excavation in the boulder strata. However, this technique has drawbacks such as uncontrollable reinforcement effect, long construction period, and high cost.

[0042] 2. For tunnels with shallow overburden, isolated boulders encountered during the tunnel boring machine's advance can be removed by creating "windows" on the surface. This method requires an open surface free of buildings or structures, presenting high construction challenges, significant safety risks, and a long construction period.

[0043] 3. The process involves removing isolated boulders one by one from the ground surface using rotary drilling rigs or rotary drilling machines. This method has the problem of inaccurate positioning of isolated boulders, and removing them in large sections can easily cause problems such as hole collapse, cross-holes, and surface subsidence. It is mainly suitable for the pretreatment of a small number of isolated boulders in a localized area.

[0044] In conclusion, improving the safety and adaptability of shield tunnels in complex environments, particularly in water-rich, boulder strata, is a pressing issue that needs to be addressed.

[0045] Example 1:

[0046] A method for constructing shield tunnels in boulder strata, such as Figures 1 to 4 As shown, it includes the following steps:

[0047] Step S101: Explore information on isolated boulders 3 along the shield tunnel 7:

[0048] Before the construction of shield tunnel 7, a detailed supplementary geological survey was conducted along the tunnel route. The survey was carried out using a combination of core drilling and GT scanning. First, the borehole survey was used to roughly understand the approximate location, size, and number of boulders 3, and to delineate the frequent occurrence areas of boulders 3. Then, GT scanning technology was used to specifically target the predicted frequent occurrence areas of boulders 3 to accurately determine the number, size, and approximate location of boulders 3.

[0049] Step S103: Construct several partition walls 2 in the frequent occurrence zone of boulder 3:

[0050] In the area prone to boulder 3, several partition walls 2 are constructed at intervals along the location of the shield tunnel 7, serving as differential pressure cutterhead replacement areas for the shield machine 6. The width of the partition wall 2 is 2 to 3 meters greater than the length of the shield machine head 6, and the height of the partition wall 2 is greater than or equal to 2 to 3 times the opening of the shield tunnel 7. Specifically, the partition wall 2 is a plain wall with unreinforced interlocking piles, with a diameter of 1.2 meters and a concrete grade of C30.

[0051] The locations of several partition walls 2 are chosen at cross-sections with a large number of isolated boulders 3, allowing for pre-treatment of most of the boulders 3 during the construction of partition walls 2, thus reducing the difficulty of subsequent jacking. For example... Figure 4 As shown, the partition wall 2 is formed by rotary drilling. Before constructing the partition wall 2, the verticality of the entire casing of the partition wall 2 should be less than 1 / 500. During construction, the actual pile length is required to be controlled according to the designed pile bottom elevation. The empty pile area from the pile top to the ground surface is backfilled with cement mortar or low-grade plain concrete to form the backfill area 5.

[0052] Step S105: Using several partition walls 2 as fulcrums, process the isolated boulders 3 on the surrounding sides:

[0053] After the construction of partition wall 2 is completed, the surrounding boulders 3 are further processed based on partition wall 2. In addition, during the jacking process, partition wall 2 is used as a fulcrum for the shield machine 6 to cut boulders 3, which solves the problem that boulders 3 are difficult to cut because they roll with the shield machine head 6, and improves the cutting efficiency of boulders 3.

[0054] Step S107: Carry out the jacking construction of shield tunnel 7:

[0055] For the Gushi 3 stratum, the preferred shield machine is a rock shield machine. During the jacking process, the tunneling parameters of the shield machine are strictly controlled. The water pressure value must be greater than or equal to the sum of the soil pressure value at the face in front of the cutterhead and the groundwater pressure. The slurry chamber pressure is required to be 0.1 bar to 0.3 bar higher than the soil and water pressure at the excavation face.

[0056] During the jacking process, it is essential to constantly monitor the stability of the excavation face, check the concentration and relative density of the slurry to ensure they are within acceptable limits, and also monitor the flow rate and pressure of the slurry pumps. Insufficient slurry pump capacity should be prevented to avoid sludge buildup and blockage in the slag discharge pipes.

[0057] When tunnel boring machine 6 enters 0.6m into the partition wall 2, it reaches the temporary stop position for inspection of the cutterhead. Before entering the enclosure for inspection, construction personnel should conduct water seepage and toxic / harmful gas detection around the working face inside the partition wall 2. If water seepage is significant, other grouting treatment measures should be taken to reduce or prevent seepage. In addition, if the detection of toxic / harmful gases in the confined space exceeds the standard, ventilation should be carried out inside the enclosure, and the inspection should only proceed after the air quality indicators meet the specifications.

[0058] Based on the inspection results, determine whether the cutterhead of shield machine 6 needs to be replaced. If replacement is required, before opening the chamber for cutter replacement, check the sealing condition of shield machine 6 after entering the partition wall 2 by empty discharge of shield machine 6. If no new slag sample is seen during the slag discharge process and the pressure is maintained well, it can be determined that the sealing of partition wall 2 meets the requirements for opening the chamber, and the chamber can be opened for cutter replacement.

[0059] Example 2:

[0060] A method for constructing shield tunnels in boulder strata, such as Figures 2 to 4 This indicates that the system includes a protective wall 1, several partition walls 2, and a shield tunnel 7. The protective wall 1 and several partition walls 2 are constructed sequentially and at intervals along the shield tunnel 7, with the partition walls 2 passing through several isolated boulders 3. In this embodiment, there are four partition walls 2, and the protective wall 1 has a near-L-shaped cross-section. Specifically, along the jacking direction of the shield equipment 6, the protective wall 1 is located in front of the partition walls 2, and a reinforcement zone 4 is set in front of the protective wall 1. That is, when the shield equipment 6 jacks up, it sequentially passes through the reinforcement zone 4, the protective wall 1, and the several partition walls 2. Figure 2 , Figure 4 The arrow in the diagram indicates the jacking direction of the shield tunneling equipment 6. Reinforcement zone 4 utilizes MJS piles for construction, and the protective wall 1 and reinforcement zone 4 protect important structures adjacent to the shield tunnel 7.

[0061] like Figure 4 As shown, the top part of the partition wall 2 to the ground is the backfill area 5, which is filled with cement mortar or low-grade plain concrete.

[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for constructing shield tunnels in boulder strata, characterized in that, Includes the following steps: Information on isolated boulders (3) along the shield tunnel (7); Several partition walls (2) are constructed in the frequent areas of the isolated rock (3); The surrounding boulders (3) are treated using several of the aforementioned partition walls (2) as fulcrums; The jacking construction of the shield tunnel (7) is carried out.

2. The method for constructing shield tunnels in boulder strata according to claim 1, characterized in that, Information on isolated boulders (3) along the exploration shield tunnel (7) route, specifically including: Distribution information of the isolated rock (3) was obtained through borehole exploration; The frequent occurrence area is determined based on the distribution information; GT scanning is performed on the frequent occurrence area to obtain information on the number, size and location of the isolated rock (3).

3. The method for constructing shield tunnels in boulder strata according to claim 2, characterized in that, Several partition walls (2) are constructed in the frequent occurrence zone of the isolated rock (3), specifically including: Backfilling is carried out in the area from the top of the partition wall (2) to the ground.

4. The method for constructing shield tunnels in boulder strata according to claim 3, characterized in that, The jacking construction of the shield tunnel (7) specifically includes: During the jacking process, the shield tunneling equipment (6) performs a cutter change after entering each of the partition walls (2).

5. The method for constructing shield tunnels in boulder strata according to claim 4, characterized in that, Before the cutterhead of the shield machine (6) is changed, the machine head of the shield machine (6) is completely inserted into the partition wall (2) by the empty discharge method of the shield machine (6). After the head of the tunnel boring machine (6) has fully entered the partition wall (2), the cutter head is changed.

6. A shield tunnel structure for boulder strata, constructed using the shield tunnel construction method for boulder strata as described in any one of claims 1 to 5, characterized in that, include: Several partition walls (2) are set at intervals along the preset route of the shield tunnel (7), and all of the partition walls (2) are located in the area where boulders (3) frequently occur; The protective wall (1) is set in front of the partition wall (2) along the direction of the shield tunnel.

7. The shield tunnel structure for boulder strata according to claim 6, characterized in that, A reinforcement zone (4) is provided on the front side of the protective wall (1).

8. The shield tunnel structure for boulder strata according to claim 6 or 7, characterized in that, The partition wall (2) uses interlocking piles.

9. The shield tunnel structure for isolated rock formations according to claim 6 or 7, wherein the width of the partition wall (2) is greater than the width of the shield machine head (6), and the height of the partition wall (2) is greater than or equal to two to three times the diameter of the shield tunnel opening.

10. The shield tunnel structure for isolated rock formations according to claim 6 or 7, wherein the shield equipment (6) is a rock shield machine.

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