Shield construction method for underneath passing of existing operating subway line

Abstract

The invention discloses a shield construction method and a heating device for underneath passing an existing operation subway line, and the method comprises the steps: obtaining a structure deformation cloud picture according to the position relation between a shield tunnel and an existing line and in combination with soil layer parameters; shield tunneling five-stage settlement control is carried out on the basis of the structural deformation cloud picture; wherein the shield tunneling five-stage settlement control comprises cutter head front settlement control, cutter head excavation position settlement control, shield tunneling machine right upper part settlement control, shield tail segment part settlement control and formed tunnel upper part lag settlement control. The problem that an existing construction method easily causes settlement or displacement overrun of an existing operation subway line can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield tunneling, in particular to a shield construction method for underpassing an existing operating subway line. BACKGROUND

[0002] Currently, the shield construction technology for underpassing an existing operating subway line by a shield tunnel is usually a method of reinforcing first and then underpassing, but when facing different environments, different stratum conditions, different overburden thicknesses and the like, the above construction method still has some problems, for example, problems of unconditioned reinforcement, unverifiable reinforcement quality, poor reinforcement quality, or problems of out-of-control construction parameters and measures in the process of tunneling, which will cause the settlement or displacement of the existing operating subway line to be out of limit, thereby causing safety and quality accidents.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application aims to provide a shield construction method for underpassing an existing operating subway line, which solves the problem that the existing construction method is easy to cause the settlement or displacement of the existing operating subway line to be out of limit.

[0005] The present application is implemented by the following technical scheme: A shield construction method for underpassing an existing operating subway line, comprising the following steps: obtaining a structure deformation cloud map according to the positional relationship between the shield tunnel and the existing line and in combination with the soil layer parameters; performing shield tunneling five-stage settlement control based on the structure deformation cloud map; The shield tunneling five-stage settlement control includes cutter head front settlement control, cutter head excavation site settlement control, shield machine directly above settlement control, out-of-shield tail pipe piece site settlement control, and formed tunnel above lag settlement control.

[0006] Optionally, the cutter head front settlement control is performed by establishing a soil chamber pressure, so that the ground surface settlement amount within 3 times the hole diameter range in front of the cutter head is (-2)-2mm. The calculation formula of the soil chamber pressure is: P=K*P0; P0=γ*h; wherein: P is the soil chamber pressure; P0 is the sum of the cutter head center stratum hydrostatic pressure and the soil pressure; γ is the average specific gravity of the soil; h is the vertical distance from the cutter head center to the ground surface; K is the lateral static soil pressure coefficient.

[0007] Optionally, settlement control at the cutterhead excavation site includes the following steps: Shield tunneling is carried out using a low cutterhead speed and a low tunneling speed. Control the amount of soil excavated during tunnel boring machine (TBM) excavation; in: The cutting head rotates at a speed of 0.8-1.0 rpm; The tunneling speed is 20-30 mm.

[0008] Optionally, controlling the amount of soil excavated during shield tunneling includes the following steps: The theoretical amount of soil removed per ring during shield tunneling was calculated. The theoretical soil removal volume of shield tunneling is obtained based on the theoretical soil removal volume per ring of shield tunneling. The actual amount of soil excavated by the shield tunneling / the theoretical amount of soil excavated by the shield tunneling is controlled to be 98-100%.

[0009] Optionally, the formula for calculating the theoretical amount of soil removed per ring of the shield tunneling is as follows: M = k1 * 1 / 4 * π * D2 * L / ring; in: M represents the theoretical amount of soil removed per ring during the shield tunneling process; k1 is the loosening coefficient of the excavated soil; D is the excavation diameter of the tunnel boring machine; L represents the single-cycle advance length.

[0010] Optionally, the settlement control above the tunnel boring machine is carried out by using radial grouting holes in the shield body to inject grout synchronously during the tunnel boring machine's excavation, filling the gap between the shield body and the excavated tunnel.

[0011] Optionally, the components of the slurry, by weight, include: Sand and gravel: 930-1298 parts, fly ash: 330-380 parts, lime: 40-80 parts, bentonite: 50-100 parts, admixtures: 3-3.5 parts, and water: 280-380 parts; in: The consistency of the slurry is 9-12 cm; The formula for calculating the grouting volume is as follows: V1 = k2 * 1 / m; in: V1 is the grouting volume of the grout; k2 is the difference between the cutterhead excavation area and the shield cross-sectional area.

[0012] Optionally, the slurry may further include 20-50 parts of cement.

[0013] Optionally, the out-of-shield tail pipe piece part settlement control is performed by synchronously pressing and injecting thick slurry through the external grouting pipe of the shield machine during the advancing process to fill the gap between the segment and the tunnel soil. Wherein: The grouting amount of the thick slurry in the upper part is 70-80%, and the grouting amount of the thick slurry in the lower part is 20-30%; The specific gravity of the thick slurry is ≥1.8g / cm 3 ; The water absorption rate of the thick slurry is ≤5%; The consistency of the thick slurry is 9-12cm; The grouting pressure of the thick slurry is 0.4-0.5MPa; The calculation formula of the grouting amount of the thick slurry is: V2=k3*1 / 4*(D2-d2)*π*L; Wherein: V2 is the grouting amount of the thick slurry; D is the excavation diameter of the shield machine; d is the outer diameter of the segment; L is the single cycle footage length; k3 is the filling rate.

[0014] Optionally, the lag settlement control above the formed tunnel comprises the following steps: When the thick slurry is initially cured, the cement-sodium silicate double slurry is used for the first segment wall back grouting above the 3-9 points of the segment; After the first segment wall back grouting is completed for 6-8h, the second segment wall back grouting is performed; Wherein: The water-cement ratio of the double slurry is (0.8-1):1; The ratio of the water glass to water of the double slurry is 1:1.5; The grouting pressure of the double slurry is 0.3-0.5MPa.

[0015] Compared with the prior art, the present application has the following advantages and beneficial effects: The shield construction method provided by the present application can control the lag settlement of the front of the cutter head, the cutter head excavation, the top of the shield body, the out-of-shield tail pipe piece, and the top of the formed tunnel during the shield machine passing through the existing operating line, so that the existing line can be fully reinforced, the continuous construction of the shield tunneling is ensured, and the safety of the existing line is also ensured. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0017] In the drawings: Fig. 1 The flow chart of the shield construction method for passing through the existing operating subway line is provided for the embodiments of the present application. Fig. 2 The five-stage schematic diagram of the influence range and settlement of the shield tunneling is provided for the embodiments of the present application. Fig. 3 The grouting distribution schematic diagram is provided for the embodiments of the present application. Fig. 4 The thick grouting schematic diagram is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0020] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0021] In the description of the embodiments of the present application, the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the application is used, or the orientation or positional relationship commonly understood by those skilled in the art, which is only for the convenience of describing the present application and simplifying the description, and is not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0022] In the description of the present application, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected, it can be directly connected, or indirectly connected through an intermediate medium, it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] Please refer to Figs. 1 to 4 The present application provides a shield construction method for underpassing an existing operating subway line, comprising the following steps: S1, obtaining a structural deformation cloud map according to the positional relationship between the shield tunnel and the existing line, in combination with the soil layer parameters; S2, performing five-stage settlement control of shield tunneling based on the structural deformation cloud map; Among them: the five-stage settlement control of shield tunneling includes cutter head front settlement control, cutter head excavation settlement control, shield machine directly above settlement control, shield tail pipe piece part settlement control and formed tunnel above lag settlement control.

[0024] The shield construction method for underpassing an existing operating subway line provided by the present application controls the cutter head front, cutter head excavation, shield body above, shield tail pipe piece and formed tunnel above lag settlement during the shield machine crossing the existing operating line, so as to fully reinforce the existing line, which ensures the continuous construction of shield tunneling and also ensures the safety of the existing line.

[0025] It should be noted that in the present embodiment, the specific implementation of step S1 is that, according to the positional relationship between the shield tunnel and the existing line, in combination with the soil layer parameters (the soil layer parameters are selected according to the actual geological exploration report), a large finite element software Midas GTSNX is used to analyze the influence of shield construction on the deformation of the existing operating subway line, so as to obtain a structural deformation cloud map, and the structural deformation cloud map is used as the theory and data basis for the control of subsequent construction steps.

[0026] In order to specifically explain the cutter head front settlement control, the cutter head front settlement control is performed. S2.1, establish the soil chamber pressure, so that the ground surface settlement amount within 3 times the hole diameter range in front of the cutter head is (-2)-2mm.

[0027] It should be noted that the soil chamber pressure is balanced with the stratum soil pressure and the hydrostatic pressure, so the calculation formula of the soil chamber pressure is: P=K*P0; P0=γ*h; Wherein: P is the soil chamber pressure; P0 is the sum of the center formation hydrostatic pressure and the soil pressure; γ is the average specific gravity of the soil; h is the vertical distance from the center of the cutter head to the ground; K is the lateral static soil pressure coefficient.

[0028] During construction, the soil chamber pressure is adjusted according to the monitoring situation and monitoring data to ensure that the ground settlement within 3 times the diameter of the cutter head is (-2) -2mm.

[0029] In order to specifically explain the cutter head excavation settlement control and reduce the disturbance of the shield machine to the soil as much as possible, the cutter head excavation settlement control comprises the following steps: S2.2.1, the shield tunneling is carried out in a low cutter head speed and low tunneling speed mode; S2.2.2, the shield tunneling earth volume is controlled; Wherein: the cutter head speed is 0.8-1.0rpm; the tunneling speed is 20-30mm.

[0030] In order to specifically explain the implementation of step S2.2.2, the control of the shield tunneling earth volume comprises the following steps: S2.2.2.1, the shield tunneling earth volume per ring is calculated; S2.2.2.2, the theoretical shield tunneling earth volume is obtained according to the shield tunneling earth volume per ring; S2.2.2.3, the actual shield tunneling earth volume / theoretical shield tunneling earth volume=98-100%.

[0031] It should be noted that the calculation formula of the shield tunneling earth volume per ring is: M=k1*1 / 4*π*D2*L / loop; Wherein: M is the shield tunneling earth volume per ring; k1 is the looseness coefficient of the excavated soil; D is the excavation diameter of the shield machine; L is the single cycle footage length (i.e. the segment width).

[0032] It should be noted that when the above steps are performed, the actual earth volume is controlled by using a belt conveyor earth weighing device and a gantry crane weighing system double control mode, and the residual earth in the residue hopper is completely emptied, which facilitates manual checking of the earth volume and prevents over-excavation.

[0033] In order to specifically explain the shield machine directly above settlement control, the shield machine directly above settlement control means: S2.3, using the radial grouting hole of the shield body, injecting slurry synchronously when the shield machine is tunneling, filling the gap between the shield body outside and the tunneling tunnel.

[0034] Since the main machine of the shield machine is composed of a cutter head, a shield body (a front shield, a middle shield and a shield tail), the diameter of the cutter head is usually 1-2 cm larger than the diameter of the shield body, with tunneling, a gap will be formed between the shield body and the soil, and the synchronous grouting filling part is behind the shield tail, which cannot fill the gap of the shield body, and the tunneling process itself disturbs the soil, and there is a settlement risk above the shield body, therefore, through the above steps, the gap is quickly filled, thereby effectively dealing with and solving the settlement risk caused by the situation.

[0035] In order to further explain the specific components of the slurry, the components of the slurry include, in parts by weight: sand and gravel: 930-1298 parts, fly ash: 330-380 parts, lime: 40-80 parts, bentonite: 50-100 parts, external admixture: 3-3.5 parts, and water: 280-380 parts; Among them: the consistency of the slurry is 9-12 cm.

[0036] It should be noted that the calculation formula of the grouting amount of the slurry is: V1=k2*1 / m; Among them: V1 is the grouting amount of the slurry; k2 is the difference between the excavation area of the cutter head and the cross-sectional area of the shield body.

[0037] Preferably, in order to shorten the setting time of the above-mentioned slurry, the components of the slurry further include cement: 20-50 parts, in order to change the performance of the slurry.

[0038] In order to specifically explain the control of the settlement of the pipe piece part out of the shield tail, the control of the settlement of the pipe piece part out of the shield tail is: S2.4, synchronously press and inject thick slurry through the external grouting pipe of the shield machine during the advancing process to fill the gap between the pipe piece and the tunnel soil.

[0039] Among them: the grouting amount of the thick slurry in the upper part is 70-80%, the grouting amount of the thick slurry in the lower part is 20-30%; the specific gravity of the thick slurry is ≥1.8 g / cm 3 ; the water absorption rate of the thick slurry is ≤5%; the consistency of the thick slurry is 9-12 cm; the grouting pressure of the thick slurry is 0.4-0.5 MPa.

[0040] Since the outer diameter of the pipe piece is smaller than the outer diameter of the shield body, when the pipe piece is out of the shield tail, a gap will be formed between the pipe piece and the soil, thereby causing a settlement risk, therefore, through the above steps, the settlement risk caused by the situation is effectively controlled; in order to consider that the slurry will deposit in the lower part due to its own gravity, thereby affecting the ground settlement and causing the pipe piece to float, the grouting amount of the thick slurry in the upper part is limited to 70-80%, and the grouting amount of the thick slurry in the lower part is 20-30%.

[0041] It should be noted that in the embodiment, a pressure sensor is arranged at the outlet of each grouting pump to detect and control the grouting pressure and grouting amount of each grouting pipe, so as to realize symmetrical and uniform pressure grouting behind the segment.

[0042] It should be noted that the calculation formula of the thick grouting amount is: V2=k3*1 / 4*(D2-d2)*π*L; Wherein, V2 is the grouting amount of the thick grouting; D is the excavation diameter of the shield machine; d is the outer diameter of the segment; L is the single cycle footage length (i.e. the segment width); k3 is the filling rate (the value range is 130-200%).

[0043] In order to specifically explain the lagging settlement control above the formed tunnel, the lagging settlement control above the formed tunnel comprises the following steps: S2.5.1, when the thick grouting is initially cured, a cement-sodium silicate double grout is used for first segment wall back grouting at the upper part of the segment 3-9 points; S2.5.2, after the first segment wall back grouting is completed for 6-8 hours, second segment wall back grouting is performed; Wherein, the water-cement ratio of the double grout is (0.8-1):1; the ratio of water glass to water of the double grout is 1:1.5; the grouting pressure of the double grout is 0.3-0.5 MPa.

[0044] Since the thick grouting will shrink to a certain extent after curing, thereby causing lagging settlement, in order to avoid the possible settlement risk in the subsequent process, the shrinkage amount is supplemented through the above steps, so as to effectively cope with the settlement risk caused by this situation.

[0045] Preferably, the embodiment can also be optimized and controlled from the following aspects: (1) According to the working condition, the control parameters and measures of shield tunneling are simulated, the influence of shield machine crossing on the existing line is deduced, and the settlement control method is improved.

[0046] (2) The posture of the shield machine strictly advances according to the designed route, and the posture is adjusted according to the principle of "frequent correction, slow correction" during tunneling, and the posture change of small amplitude correction is ≤3mm per ring.

[0047] (3) P, k2, k3 and the back wall grouting pressure are determined by the test section, which meets the five settlement stages of shield tunneling, i.e. the front of the cutter head, the cutter head excavation, the top of the shield body, the segment at the tail of the shield, and the lagging settlement above the formed tunnel, which is controlled in a micro-undulating state, and the settlement amount is controlled in the range of (-2)-2mm.

[0048] (4) Existing line settlement monitoring uses automatic monitoring system, after entering the influence range of the crossing section, the monitoring is encrypted, and a monitoring report is generated once an hour to guide the adjustment of the excavation construction parameters.

[0049] (5) At the construction organization level, before the shield machine reaches the influence range of the crossing, the shield machine and the supporting equipment are comprehensively maintained, the spare parts of the easily damaged components are in place, the construction materials are prepared in sufficient quantity, the external environment such as earthwork external transportation is coordinated, and the continuous construction is ensured.

[0050] (6) Non-planned shutdown measures are formulated to avoid uncontrollable settlement during the period.

[0051] The above specific embodiments further specifically describe the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A shield construction method for underpassing an existing operating subway line, characterized by, It comprises the following steps: According to the position relationship between the shield tunnel and the existing line, and the soil layer parameters, a structure deformation cloud chart is obtained; According to the structure deformation cloud chart, five-stage settlement control during shield tunneling is performed; The five-stage settlement control during shield tunneling comprises cutter head front settlement control, cutter head excavation settlement control, shield machine directly above settlement control, shield tail pipe piece part settlement control, and formed tunnel above lag settlement control.

2. The method of shield construction for underpassing an existing operating subway line according to claim 1, characterized in that, The cutter head front settlement control is performed by establishing soil chamber pressure, so that the ground surface settlement within 3 times the hole diameter range in front of the cutter head is (-2)-2mm. The calculation formula of the soil chamber pressure is: P=K*P0; P0=γ*h; Wherein: P is the soil chamber pressure; P0 is the sum of the cutter head center ground static water pressure and the soil pressure; γ is the average specific gravity of the soil; h is the vertical distance from the cutter head center to the ground surface; K is the lateral static soil pressure coefficient.

3. The method of shield construction for underpassing an existing operating subway line according to claim 1, wherein The cutter head excavation settlement control comprises the following steps: Shield tunneling is performed by using low cutter head rotating speed and low tunneling speed; The shield tunneling soil quantity is controlled; Wherein: The cutter head rotating speed is 0.8-1.0rpm; The tunneling speed is 20-30mm.

4. The method of shield construction for underpassing an existing operating subway line according to claim 3, wherein The control of the shield tunneling soil quantity comprises the following steps: The shield tunneling each ring theoretical soil quantity is calculated; The theoretical shield tunneling soil quantity is obtained according to the shield tunneling each ring theoretical soil quantity; The actual shield tunneling soil quantity / theoretical shield tunneling soil quantity=98-100%.

5. The method of shield construction for underpassing an existing operating subway line according to claim 4, wherein The calculation formula of the shield tunneling each ring theoretical soil quantity is: M=k1*1 / 4*π*D2*L / loop; Wherein: M is the shield tunneling each ring theoretical soil quantity; k1 is the looseness coefficient of the excavation stratum soil; D is the excavation diameter of the shield machine; L is the single cycle footage length.

6. The method of shield construction for underpassing an existing operating subway line according to claim 1, wherein The shield machine directly above settlement control is performed by using the radial grouting hole of the shield body, and the slurry is injected synchronously during the shield machine tunneling to fill the gap between the shield body outside and the tunneling tunnel.

7. The method of shielded construction of a tunnel beneath an existing operational metro railway line according to claim 6, wherein, The components of the slurry include, by weight: Sand and stone: 930-1298 parts, fly ash: 330-380 parts, lime: 40-80 parts, bentonite: 50-100 parts, external admixture: 3-3.5 parts, and water: 280-380 parts; Wherein: The consistency of the slurry is 9-12cm; The calculation formula of the grouting quantity of the slurry is: V1=k2*1 / m; Wherein: V1 is the grouting quantity of the slurry; k2 is the difference between the cutter head excavation area and the shield body cross-sectional area.

8. The method of shielded construction of a tunnel beneath an existing operational metro railway line according to claim 7, wherein, The components of the slurry further include cement: 20-50 parts.

9. The method of shield construction for underpassing an existing operating subway line according to claim 1, wherein The shield tail pipe piece part settlement control is performed by synchronously pressing and injecting thick slurry through the external grouting pipe of the shield machine during the advancing process to fill the gap between the pipe piece and the tunneling tunnel soil; Wherein: The grouting quantity of the thick slurry in the upper part is 70-80%, and the grouting quantity of the thick slurry in the lower part is 20-30%; The thick paste has a specific gravity ≥ 1.8 g / cm 3 ; The water absorption rate of the thick slurry is ≤5%; The consistency of the thick slurry is 9-12cm; The grouting pressure of the thick slurry is 0.4-0.5MPa; The calculation formula of the grouting quantity of the thick slurry is: V2=k3*1 / 4*(D2-d2)*π*L; Wherein: V2 is the grouting amount of the thick paste; D is the excavation diameter of the shield machine; d is the outer diameter of the segment; L is the single cycle footage length; k3 is the filling rate.

10. The method of shield construction for underpassing an existing operating subway line according to claim 1, wherein The lag settlement control above the formed tunnel comprises the following steps: When the thick paste is initially cured, the cement-sodium silicate double paste is used for the first segment wall back grouting at the upper part of the segment 3-9 points; After the first segment wall back grouting is completed for 6-8 hours, the second segment wall back grouting is performed; Wherein: The water-cement ratio of the double paste is (0.8-1):1; The ratio of sodium silicate to water of the double paste is 1:1.5; The grouting pressure of the double paste is 0.3-0.5 MPa.

Images