LU505088B1

LU505088B1 - Boulder detection treatment and construction method for shield tunneling of old building region

Info

Publication number: LU505088B1
Application number: LU505088A
Authority: LU
Inventors: guangdong Lu; Gang Zhao; Xinya Sun; Qiao Zhang; Guohui Wu; Yongjun Shao; Song Luo; Cheng Zhang; Along Xu; Ping Jin; Yingxian Lu
Original assignee: China Railway South Invest Group Co Ltd; China Tiesiju Civil Eng Group Co Ltd
Priority date: 2023-06-09
Filing date: 2023-09-14
Publication date: 2024-03-15
Also published as: CN116556963A

Abstract

The present disclosure relates to the technical field of shield construction and, in particular, to a boulder detection treatment and construction method for shield tunneling of an old building region. The method includes the following steps: S1, performing Computer Tomography (CT) scanning detection on a boulder located under a building, and finding out a spatial position and size of the boulder; S2, arranging, according to a CT scanning result, hole sites for drilling the boulders on grounds on two sides of the building; S3, drilling the boulder through drilling equipment and the hole sites for drilling; S4, plugging polyvinyl chloride (PVC) pipes into drill holes after the drilling is completed; S5, grouting a periphery of a shield tunnel through the PVC pipes for pre-reinforcement; and S6, sealing and cleaning the grouted drill holes. The method not only ensures that the boulder hindering the construction can be cleared during shield tunnel construction and will not destroy the building above the shield tunnel, but also reduces the construction costs, shortens the construction period, and improves the construction efficiency of projects.

Description

BOULDER DETECTION TREATMENT AND CONSTRUCTION METHOD FOR

LU505088

SHIELD TUNNELING OF OLD BUILDING REGION

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of shield tunneling and, in particular, to a boulder detection treatment and construction method for shield tunneling of an old building region.

BACKGROUND

[0002] With the acceleration of urbanization in China, the increasing urban population brings more and more obvious pressure to urban traffic. However, the development of urbanization definitely cannot be constrained by traffic pressure, so underground traffic which corresponds to traditional surface traffic has become a new way to alleviate the traffic pressure of cities. Subway traffic 1s a green project that is in line with the sustainable development strategy of China and has gradually been promoted in medium and large-sized cities. In the process of constructing subways, construction of shield tunnels is involved. Due to the complexity of surrounding buildings in different cities, shield tunnels may usually pass through some buildings. In a shield tunneling process, the shield tunnels need to pass through complex strata under the buildings, especially strata that are soft at the top and hard at the bottom and contain boulders.

[0003] For the strata that are soft at the top and hard at the bottom and contain boulders, a current conventional method of shield construction for solving this problem generally uses a traditional mining method such as rock breaking with a shield tunneling machine, manual rock breaking, static blasting inside a tunnel, and gunpowder blasting to treat boulders. If a boulder 1s located below an old building group, the above methods are likely to cause significant disturbance to the strata and endanger the safety of houses. When the traditional mining methods are used, old houses need to be demolished, which causes a series of problems such as high investment costs, serious delay in a demolition process, and cumbersome procedures for house demolition. Therefore, there is an urgent need to solve these problems.

[0004] The above content 1s only used to assist in understanding the technical solutions of the present disclosure, and does not represent that the above content is the latest prior art.

SUMMARY

[0005] The technical problem to be solved in the present disclosure is to provide a boulder detection treatment and construction method for shield tunneling of an old building region. The method not only ensures that boulders hindering construction can be cleared during shield tunnel 1/12 construction and will not destroy buildings above a shield tunnel, but also reduces the construction

LU505088 costs, shortens the construction period, and improves the construction efficiency of projects.

[0006] In order to achieve the objectives, the technical solutions of the present disclosure are achieved below: A boulder detection treatment and construction method for shield tunneling of an old building region is provided. The method includes the following steps:

[0007] S1, performing Computer Tomography (CT) scanning detection on a boulder located under a building and located in a cross section of a construction path of a shield tunnel, and finding out a spatial position and size of the boulder;

[0008] S2, arranging, according to a CT scanning result, hole sites for drilling the boulder on a ground) around the building;

[0009] S3, drilling the boulder through drilling equipment and the hole sites for drilling, so as to pre-crack the boulder;

[0010] S4, drilling soil around the cross section of the construction path of the shield tunnel through the drilling equipment;

[0011] SS, plugging polyvinyl chloride (PVC) pipes into drill holes after the drilling is completed;

[0012] S6, grouting the boulder and the soil around the cross section of the construction path of the shield tunnel through the PVC pipes for pre-reinforcement, and forming a grouted reinforcement body inside and outside the cross section of the construction path of the shield tunnel; and

[0013] S7, sealing and cleaning the grouted drill holes.

[0014] Preferably, the CT scanning detection uses a sector penetration method, which is combined with an inversion algorithm to obtain the spatial position and morphological features of the boulder.

[0015] Preferably, in step S3, the method for drilling the boulder is to perforate a surface of the boulder obliquely and densely, and a distance between the respective drill holes on the boulder is 600 mm*600 mm; and the respective drill holes are distributed in a plum blossom shape along the surface of the boulder.

[0016] Preferably, grouting slurry is binary slurry prepared by mixing cement slurry with sodium silicate slurry, and backward grouting is used; when pressure reaches 2.5 MPa, the drilling equipment is lifted by 1 m; a longitudinal range of the grouting reinforcement is at least twice a diameter of the boulder C, and a transverse reinforcement range covers the cross section of the construction path of the shield tunnel 10 and the soil within 3 m around the shield tunnel. 2/12

[0017] Preferably, a volume ratio of the cement slurry to the sodium silicate slurry in the grouting

LU505088 slurry is 1:1; a volume ratio of cement to water in the cement slurry is 1:0.8; and a volume ratio of sodium silicate to water in the sodium silicate slurry is 1:1.

[0018] Preferably, the drill holes on the boulder are through holes and extend into the cross section of the construction path of the shield tunnel.

[0019] Preferably, the drill holes on the soil around the cross section of the construction path of the shield tunnel are distributed at equal intervals.

[0020] Preferably, the PVC pipes are processed into grouting pipes, each having a diameter of 30 mm.

[0021] Preferably, a center of each PVC pipe overlaps a center of each drill hole, and a length of the PVC pipe is 0.3 m greater than a depth of the drill hole.

[0022] Preferably, a pipe orifice of the PVC pipe is sleeved with a protective cap.

[0023] The present disclosure has the beneficial effects below:

[0024] (1) In the present disclosure, the boulder is pre-cracked in a ground drilling way, and the drill holes on the boulder and the drill holes on the soil around the construction path of the shield tunnel are grouted. The injected slurry seeps along a pre-cracked gap of the boulder and is mixed with slurry in the soil around the construction path of the shield tunnel. The solidified slurry fixes the cracked boulder. This causes the boulder that is originally scattered on the construction path of the shield tunnel and a soil layer to form a whole, that is, to form the grouted reinforcement body on the construction path of the shield tunnel. When a shield tunneling machine performs tunnel construction on the grouted reinforcement body, the shield tunneling machine can only excavate a tunnel in the grouted reinforcement body, instead of causing a phenomenon of collapse of both the boulder that is located above the shield tunnel and the soil layer due to the scattering of the boulder. This method for treating a boulder below a building not only avoids the influence on a building above the shield tunnel, but also accelerates the shield construction and effectively shortens the construction period.

[0025] (2) The method for treating a boulder under an old house, which is provided in the present disclosure, can minimize the influence of the shield construction and the boulder treatment on houses and ensure the safety of the house.

[0026] (3) The present disclosure uses the ground drilling way to break relatively large boulders, which reduces the wear of boulders on tools during the shield construction, avoids risks such as sudden changes in shield postures caused by boulders, and improves the safety of construction.

[0027] (4) The grouting slurry used in the present disclosure is the binary slurry prepared by 3/12 mixing the cement slurry with the sodium silicate slurry, both of which are environmentally-

LU505088 friendly materials and may not pollute soil, so that the influence on a surrounding environment is effectively reduced, and green construction 1s achieved.

[0028] (5) The method provided in the present disclosure ensures that the center of the PVC pipe overlaps the center of the drill hole, which can allow the PVC pipe to be fully plugged into the drill hole, so that post-grouting slurry can smoothly reach the position where the boulder is located.

In actual construction, the length of the PVC pipe 1s 0.3 m greater than the depth of the drill hole, which avoids pipe blockage caused by the fact that soil or debris around the drill hole falls into the

PVC pipe.

[0029] (6) In the method provided in the present disclosure, the method for drilling the boulder is to perforate the surface of the boulder obliquely and densely. This perforation method can ensure successful perforation of the boulder located directly below the building from a side surface of the building, which reduces the construction difficulty. In addition, the distance between the drill holes on the boulder is 600 mm* 600 mm, thus forming dense drill holes on the boulder, so that the boulder can be pre-cracked, and the boulder with the relatively large volume is divided into small pieces. The respective drill holes are distributed in the plum blossom shape along the surface of the boulder, so that the boulder is pre-cracked uniformly. It is convenient for the slurry to more fully connect or wrap the boulder in the later stage of grouting fixing. Meanwhile, internal stress of the overall structure of the formed grouted reinforcement body is more stable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a flowchart of a method of the present disclosure;

[0031] FIG. 2 is a schematic diagram of positions of a boulder, a shield tunnel, and a building of the present disclosure; and

[0032] FIG. 3 is a schematic diagram of grouting construction of the present disclosure.

[0033] Reference numerals in the drawings:

[0034] A: building; B: ground; C: boulder;

[0035] 10: shield tunnel; 20: PVC pipe; and 30: grouted reinforcement body.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below in combination with the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are only part of the embodiments of the present disclosure, not all embodiments. The embodiments in this 4/12 application and features in the embodiments may be combined with each other without conflicts.

LU505088

Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without doing creative work shall fall within the protection scope of the present disclosure.

[0037] Embodiment 1

[0038] As shown in FIG. 1 to FIG. 3:

[0039] The present disclosure provides a boulder detection treatment and construction method for shield tunneling of an old building region. The method includes the following steps:

[0040] S1, performing CT scanning detection on a boulder C located under a building A and located in a cross section of a construction path of a shield tunnel 10, and finding out a spatial position and size of the boulder C.

[0041] The CT scanning uses sector penetration with one transmitter and multiple receives.

Through point by point excitation, a dense ray crossing network is formed in a tested region. When

CT scanning data 1s processed, the tested region is divided into several regular imaging units according to the sparsity and imaging accuracy of rays. In this way, it can be considered that each imaging unit has uniform geological medium and a single wave velocity. An inversion algorithm is then used to precisely obtain the spatial position and morphological features of the boulder C.

[0042] S2, arranging, according to a CT scanning result, hole sites for drilling the boulder C on a ground B around the building A.

[0043] S3, drilling the boulder C through drilling equipment and hole sites for drilling. During drilling, a geological drilling rig with a comprehensive drilling bit is used for construction. A diameter of the drilling bit shall be greater than a designed hole diameter of a drill hole. The final hole shall not be too large or smaller than the designed hole diameter of the drill hole, so as to ensure that a PVC pipe 20 can be smoothly plugged into the drill hole.

[0044] During the drilling operation, the surface of the boulder C is perforated obliquely and densely, and a distance between the respective drill holes is 600 mm*600 mm. The drill holes are distributed in a plum blossom shape. The boulder C and bed rock in the construction path of the shield tunnel 10 are pre-cracked and invaded in advance in this way, which reduces the integrities of the boulder C and the bed rock.

[0045] A drilling treatment range for the boulder C and the bed rock is within 0.95 m on each of two sides of the construction path of the shield tunnel 10, and at the same time, the drill holes penetrate through the boulder C until the drill holes extend into the cross section of the construction path of the shield tunnel 10. 5/12

[0046] S4, drilling soil around the cross section of the construction path of the shield tunnel (10) through drilling equipment at equal intervals. 7505098

[0047] SS, plugging PVC pipes 20 into the drill holes after the drilling is completed, where the

PVC pipes 20are grouting pipes, each having a diameter of 30 mm. The PVC pipes are processed into the grouting pipes in advance. The PVC pipes 20 should be plugged into the drill holes immediately after the drilling is completed, so as to prevent a phenomenon that the PVC pipes 20 cannot be plugged due to internal collapse of the drill holes caused by a long time interval.

[0048] In addition, when the PVC pipes 20 are lowered along the drill holes, joint connection is used. Throughout the mounting process, it should be ensured that a center of each PVC pipe 20 overlaps a center of each drill hole, thereby ensuring that the PVC pipe 20 can be lowered to the bottommost portion of the drill hole. Meanwhile, a length of the PVC pipe 20 is determined according to an actual drilling depth. During the mounting of the PVC pipe 20,the PVC pipe needs to be 0.3 m above the ground B. Therefore, an actual mounting length of the PVC pipe 20 is equal to a hole depth plus 0.3 m. A pipe orifice of the PVC pipe 20 is sleeved with a protective cap, which can prevent debris from entering the PVC pipe 20 before grouting.

[0049] S6, grouting the boulder C and the soil around the cross section of the construction path of the shield tunnel 10 through the PVC pipes 20 for pre-reinforcement, and forming a grouted reinforcement body 30 inside and outside the cross section of the construction path of the shield tunnel 10.

[0050] According to a grouting range, the surrounding soil above the waist of the cross section of the construction path of the shield tunnel 10 is grouted for pre-reinforcement, thereby fixing the position of the broken boulder C. Moreover, the soil at a vault of the cross section of the construction path of the shield tunnel 10 is grouted for pre-reinforcement, so that during actual construction, the disturbance to strata when a shield tunneling machine breaks the boulder C can be reduced.

[0051] Grouting slurry is binary slurry prepared by mixing cement slurry with sodium silicate slurry, and backward grouting is used. When pressure reaches 2.5 MPa, the drilling equipment is lifted by 1 m. A longitudinal range of the grouting is at least twice a diameter of the boulder C, and a transverse reinforcement range covers the cross section of the construction path of the shield tunnel 10 and the soil within 3 m outside the shield tunnel.

[0052] A ratio of the cement slurry to the sodium silicate slurry for grouting reinforcement is as follows: 6/12

Slurry A (mass ratio) Slurry B (volume ratio) Slurry A: Slurry B LU505088

Cement: water=1:0.8 Sodium silicate: water =1:1

[0053] S7, sealing and cleaning the grouted drill holes.

[0054] The above is only the preferred embodiments of the present disclosure, and is not intended to limit the present disclosure. Any modifications, equivalent replacements and improvements that are made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure. 7/12

Claims

CLAIMS LU505088

1. A boulder detection treatment and construction method for shield tunneling of an old building region, wherein the method comprises the following steps: S1, performing Computer Tomography (CT) scanning detection on a boulder (C) located under a building (A) and located in a cross section of a construction path of a shield tunnel (10), and finding out a spatial position and size of the boulder (C); S2, arranging, according to a CT scanning result, hole sites for drilling the boulder (C) on a ground (B) around the building (A); S3, drilling the boulder (C) through drilling equipment and the hole sites for drilling, so as to pre-crack the boulder (C); S4, drilling soil around the cross section of the construction path of the shield tunnel (10) through the drilling equipment; SS, plugging polyvinyl chloride (PVC) pipes (20) into drill holes after the drilling is completed; S6, grouting the boulder (C) and the soil around the cross section of the construction path of the shield tunnel (10) through the PVC pipes (20) for pre-reinforcement, and forming a grouted reinforcement body (30) inside and outside the cross section of the construction path of the shield tunnel (10); and S7, sealing and cleaning the grouted drill holes.

2. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 1, wherein the CT scanning detection uses a sector penetration method, which is combined with an inversion algorithm to obtain the spatial position and morphological features of the boulder (C).

3. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 1, wherein in step S3, the method for drilling the boulder (C) is to perforate a surface of the boulder (C) obliquely and densely, and a distance between the respective drill holes on the boulder (C) is 600 mm*600 mm; and the respective drill holes are distributed in a plum blossom shape along the surface of the boulder (C).

4. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 3, wherein grouting slurry is binary slurry prepared by mixing cement slurry with sodium silicate slurry, and backward grouting is used; when pressure reaches

2.5 MPa, the drilling equipment is lifted by 1 m; a longitudinal range of the grouting reinforcement 8/12 is at least twice a diameter of the boulder C, and a transverse reinforcement range covers the cross LU505088 section of the construction path of the shield tunnel 10 and the soil within 3 m around the shield tunnel.

5. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 4, wherein a volume ratio of the cement slurry to the sodium silicate slurry in the grouting slurry is 1:1; a volume ratio of cement to water in the cement slurry is 1:0.8; and a volume ratio of sodium silicate to water in the sodium silicate slurry is 1:1.

6. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 3 or 4 or 5, wherein the drill holes on the boulder (C) are through holes and extend into the cross section of the construction path of the shield tunnel (10).

7. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 5, wherein the drill holes on the soil around the cross section of the construction path of the shield tunnel (10) are distributed at equal intervals.

8. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 6, wherein the PVC pipes (20) are processed into grouting pipes, each having a diameter of 30 mm.

9. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 8, wherein a center of each PVC pipe (20) overlaps a center of each drill hole, and a length of the PVC pipe (20) is 0.3 m greater than a depth of the drill hole.

10. The boulder detection treatment and construction method for shield tunneling of the old building region according to claim 9, wherein a pipe orifice of the PVC pipe (20) 1s sleeved with a protective cap. 9/1