CN115306397A - Unloading balance construction method for newly-built rectangular pipe-jacking upward-penetrating existing subway tunnel - Google Patents

Unloading balance construction method for newly-built rectangular pipe-jacking upward-penetrating existing subway tunnel Download PDF

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CN115306397A
CN115306397A CN202210774164.4A CN202210774164A CN115306397A CN 115306397 A CN115306397 A CN 115306397A CN 202210774164 A CN202210774164 A CN 202210774164A CN 115306397 A CN115306397 A CN 115306397A
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pipe
jacking
tunnel
existing
deformation
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李忠超
张志伟
霍超
吴斌
谭冲
梁荣柱
黄超群
刘律
黄栋
李徐德
彭静
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China University of Geosciences
Wuhan Municipal Construction Group Co Ltd
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China University of Geosciences
Wuhan Municipal Construction Group Co Ltd
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/001—Improving soil or rock, e.g. by freezing; Injections
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/001—Improving soil or rock, e.g. by freezing; Injections
    • E21D9/002—Injection methods characterised by the chemical composition used
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/003—Arrangement of measuring or indicating devices for use during driving of tunnels, e.g. for guiding machines
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/10—Making by using boring or cutting machines
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
    • E21F17/18—Special adaptations of signalling or alarm devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/20—Hydro energy

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Soil Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Excavating Of Shafts Or Tunnels (AREA)

Abstract

An unloading balance construction method for a newly-built rectangular pipe jacking upward-penetrating existing subway tunnel comprises the following steps: arranging existing tunnel deformation monitoring points; calculating an excavation influence range; measuring and lofting, installing a push bench rack, a rear support device and a main jacking device, debugging equipment and entering a tunnel by the push bench; hoisting the cushion block and the pipe joint; jacking and measuring a jacking pipe; pressing and injecting soil consolidation slurry; monitoring the deformation of the existing tunnel; judging the maximum uplift value of the tunnel, and determining whether ballast measures are taken or not according to whether the vertical displacement value of the maximum vault of the existing tunnel is greater than or equal to a set early warning value or not; stacking and loading the weight; and (4) discharging the pipe jacking machine. According to the method, targeted deformation control measures are taken for the existing tunnel according to the calculated excavation influence range and the tunnel deformation dynamic monitoring result, so that the loss of manpower and material resources caused by blind control is avoided; according to an unloading balance method, the pile-loading pressure weight of the pipe sections is balanced to balance the unloading stress generated by the soil layer below, so that the aim of controlling the deformation of the existing tunnel can be effectively fulfilled; high construction efficiency and low cost.

Description

Unloading balance construction method for newly-built rectangular top pipe to pass through existing subway tunnel
Technical Field
The invention belongs to the technical field of subway shield tunnels, and particularly relates to an unloading balance construction method for a newly-built rectangular top pipe to pass through an existing subway tunnel, which is particularly suitable for a rectangular top pipe to pass through the existing subway tunnel engineering in soft soil areas where deformation of the existing tunnel needs to be strictly controlled.
Background
Along with the continuous improvement of urban underground traffic networks, the problem that newly-built rectangular jacking pipes penetrate through existing subway tunnels inevitably occurs in limited urban underground space. The weight of the excavated soil mass of the top pipe excavation is far larger than that of the installed pipe joints, an unloading effect can be generated, so that the existing subway tunnel below is caused to bulge and deform wholly or locally, a series of diseases such as pipe segment damage and water seepage, joint opening, longitudinal uneven settlement and the like are generated in the shield tunnel structure below, and serious accidents such as locomotive derailment and the like can be caused by serious people. In the process of crossing construction of urban underground rectangular pipe-jacking tunnels, the traditional construction method is to reinforce the peripheral stratum of the existing tunnel in advance, and the reinforcement mode has very high cost in the engineering, so that a novel construction process adaptive to the construction of newly-built rectangular pipe-jacking above the existing subway tunnel is developed on the basis of ensuring the normal and safe operation of the existing subway tunnel and controlling the deformation of the surrounding soil body, and the construction method has extremely high social and economic benefits.
Disclosure of Invention
The technical problem to be solved by the invention is to provide an unloading balance construction method for a newly-built rectangular top pipe to pass through an existing subway tunnel, aiming at the problems existing in the existing top pipe tunnel excavation, so that the deformation of the existing subway tunnel under the top-passing construction of the newly-built rectangular top pipe is effectively controlled, and the loss of manpower and material resources caused by blind control is avoided; high construction efficiency and low cost.
The technical scheme adopted by the invention for solving the technical problems is as follows:
an unloading balance construction method for a newly-built rectangular top pipe to pass through an existing subway tunnel comprises the following steps:
s1, arranging existing tunnel deformation monitoring points;
s2, calculating an excavation influence range, and regarding the existing tunnel as a Timoshenko beam model placed on a Passternak foundation to obtain a main range of influence of the longitudinal deformation of the existing tunnel on a newly-built pipe-jacking tunnel;
s3, measuring and lofting, installing a push bench frame, a backrest and a main jacking device, debugging equipment and entering a hole by the push bench;
s4, hoisting the cushion block and the pipe joint;
s5, jacking and measuring the jacking pipe;
s6, pressing and injecting soil body consolidation grout, and pressing and injecting the consolidation grout in time through the pipe wall grouting holes when the jacking pipe is jacked in, so that the grout permeates into a soil layer around the jacking pipe and is hardened in the soil layer, and thus the soil layer is reinforced;
s7, monitoring the deformation of the existing tunnel;
s8, judging the maximum crown value of the tunnel, and if the monitored vertical displacement value of the maximum vault of the existing tunnel is smaller than a set early warning value before the excavated surface enters a main influence area, not taking ballast measures for the pipe joints, and subsequently determining whether to take ballast measures according to whether the monitored vertical displacement value of the maximum vault of the existing tunnel is larger than or equal to the set early warning value in the pipe-jacking tunneling process; if no ballast measures are taken, repeating the steps S4-S7 until the pipe jacking machine goes out of the hole in the step S10;
s9, carrying out ballast weight, and taking ballast measures on the pipe joints if the monitored vertical displacement value of the maximum vault of the existing tunnel is greater than or equal to a set early warning value before the excavation face enters a main influence area or in the subsequent excavation process;
and S10, after the machine head reaches the receiving well, the pipe jacking machine goes out of the hole.
According to the scheme, the step S1 specifically comprises the following steps: arranging deformation monitoring points on an existing subway tunnel 1-2 months before the formal construction of a jacking pipe, wherein the arrangement range of deformation monitoring sections of the existing subway tunnel is 60m away from the left side and the right side of the intersection point of the plane of a new tunnel and an old tunnel, the arrangement intervals are arranged according to 5m, 10m and 20m from the two sides of the jacking axis of the jacking pipe, and 5 prisms are arranged in all sections, wherein the first prism is arranged at the topmost part of the center of each section and is used for monitoring the vertical displacement of the vault of the tunnel; the second prism and the third prism are arranged at two ends of the horizontal axis of the section and are used for monitoring the clearance convergence of the tunnel; the fourth prism and the fifth prism are respectively arranged on the track bed and are respectively used for monitoring the horizontal displacement and the vertical displacement of the track bed.
According to the scheme, the step S2 specifically comprises the following steps: the method comprises the following steps of calculating a change graph of the maximum uplift value of the existing tunnel along with the excavation distance by adopting a Mindlin solution and a finite difference method, determining an interval with no obvious change of the uplift value as a secondary influence area, and determining an interval with obvious change as a main influence area, wherein the method specifically comprises the following steps of: the excavation surface is a primary influence area within 3 times of the width range of the newly built jacking pipe from the existing tunnel axis, and a secondary influence area outside the 3 times of the width range of the newly built jacking pipe.
According to the scheme, the hole entering of the push bench in the step S3 specifically comprises the following steps: after the measurement and lofting are finished, installing a frame, a backrest and a main jacking device of the pipe jacking machine, debugging equipment, and operating the pipe jacking machine to enter a hole after the hole breaking door works; the hoisting cushion block and the pipe joint are specifically as follows: after the pipe jacking jack jacks a pipe joint, the cushion block and the pipe joint are timely lifted, and a new pipe joint is installed.
According to the scheme, the step S5 of jacking and measuring the jacking pipe specifically comprises the following steps:
the jacking speed v of the jacking pipe is controlled to be 3.5-4 m/d in the secondary influence area obtained by calculation in the step two, the jacking force F is controlled to be 2-3 m/d in the primary influence area, the jacking force F is calculated according to the formula (1) by combining with the engineering condition, and other construction parameters need to be dynamically adjusted according to the deformation feedback data of the earth surface and the tunnel continuously to achieve the optimal state:
F＝F 1 +F 2 (1)
in the formula: f is the minimum jacking force in kN; f 1 Is the frictional resistance of the pipeline and the soil layer, and has the unit kN, F 1 L is the jacking length of the jacking pipe and the unit m is = (a + b) × 2lf; f is the average frictional resistance between the outer wall of the pipeline and the soil, and the unit kN/m 2 Preferably 7 to 12kN/m 2 ；F 2 Is the head-on resistance of the push bench in kN, F 2 ＝a×bR 1 ，R 1 The passive earth pressure at 1/3 of the lower part of the push bench is expressed in kN; a is the width of the push bench in m; and b is the height of the push bench in m.
According to the scheme, the grouting sequence of the step S6 of grouting the soil consolidation slurry specifically comprises the following steps: mixing slurry on the ground → starting a mud pump → opening a valve of a main pipe → opening a valve of a pipe joint → delivering slurry → closing the valve of the pipe joint → closing the valve of the main pipe valve → disassembling a quick joint in the well → connecting a lower pipe joint → connecting a 2-inch main pipe → repeating; grouting materials and proportioning: the cementing material adopts P042.5 cement, and the slurry ratio is controlled in the following range: 0.5.
According to the scheme, the step S7 of monitoring the deformation of the existing tunnel specifically comprises the following steps: in the jacking process of the jacking pipe, monitoring the deformation of the existing shield tunnel by using an intelligent total station; when the excavation surface of the jacking pipe is in a secondary influence area, monitoring frequency is 1-2 times/day; when the excavation surface of the jacking pipe is in a main influence area, the monitoring frequency is 3-4 times/day.
According to the scheme, the setting range of the early warning value in the step S8 and the step S9 is 3-5 mm.
According to the scheme, the concrete steps of taking ballast measures for the pipe sections in the step S9 are as follows:
s91, if the heaping load is carried out before the pipe jacking excavation surface enters the main influence area, after the capacity of a pipe joint is excavated on the soil body in front of the tunnel by the pipe jacking machine each time, the weight difference between the excavated soil body and the pipe joint is calculated in time, and the heaping load is carried out on the pipe joint in the main influence area by adopting prefabricated C20 plain concrete or iron blocks with the same weight difference; (ii) a After the soil body of each pipe joint is excavated until the pile loading weight is finished, carrying out subsequent soil body excavation work; when the ballasted pipe joint leaves the main influence area, the ballasted plain concrete or iron blocks are moved away to the pipe joint which subsequently enters the main influence area;
and S92, if the pile loading is carried out in the subsequent tunneling process, immediately carrying out pile loading and weight pressing on all pipe joints in the main influence area, wherein the specific steps are consistent with the step S91.
According to the scheme, the step S10 of hole outlet of the pipe pushing jack specifically comprises two conditions:
s101, if ballast measures are not taken in the whole jacking process of the jacking pipe, the jacking pipe is decomposed and hoisted out of a receiving well, then slurry replacement is carried out, and the treatment of pipe internal equipment, caulking, cleaning and joint treatment is carried out;
s102, if ballast measures are taken for the jacking pipe, grouting and reinforcing a soil layer in the main influence area through a pipe joint grouting hole after the jacking pipe is completely penetrated; after grouting reinforcement, removing the stacked objects section by section, synchronously monitoring the deformation of the existing tunnel, if the deformation of the existing tunnel is stable after each section of stacked object is removed, continuously removing the next section of heavy object until all the stacked objects are removed, and if the deformation is unstable, continuously grouting or taking other stratum reinforcement measures until the removed stacked objects do not influence the subsequent deformation of the tunnel; and after the tunnel is deformed stably, the pipe jacking machine is disassembled, and the receiving well is hoisted out and then works.
The beneficial effects of the invention are as follows:
1. according to the calculated excavation influence range and the tunnel deformation dynamic monitoring result, a targeted deformation control measure is adopted for the existing tunnel, so that the loss of manpower and material resources caused by blind control can be avoided;
2. according to an unloading balance method, the pile-loading pressure weight of the pipe sections is balanced to balance the unloading stress generated by the soil layer below, so that the aim of controlling the deformation of the existing tunnel can be effectively fulfilled;
3. the construction method is simple, the operation is simple and convenient, the construction efficiency is high, and the cost is low.
Drawings
FIG. 1 is a flow chart of an unloading balance construction method for newly-built pipe-jacking and upward-penetrating existing subway tunnels in the embodiment of the invention;
FIG. 2 is a layout diagram of deformation monitoring points of a section of an existing shield tunnel in the embodiment of the invention;
FIG. 3 is a calculation model of the influence range of newly built jacking pipe excavation in the embodiment of the invention;
FIG. 4 shows the main influence area of newly built jacking pipe excavation in the embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and examples.
The invention relates to an unloading balance construction method for a newly-built pipe jacking and upward-passing existing subway tunnel, which comprises the steps of arranging deformation monitoring points of the existing tunnel, calculating an excavation influence range, entering a tunnel by a pipe jacking machine, hoisting cushion blocks and pipe joints, jacking and measuring the pipe jacking machine, grouting soil consolidation slurry, monitoring the deformation of the existing tunnel, judging the maximum bulging value of the tunnel, piling load and pressing weight, and discharging the pipe jacking machine from the tunnel. The whole method flow chart is shown in fig. 1, and specifically comprises the following steps:
step one, arranging existing tunnel deformation monitoring points
Deformation monitoring points are arranged on an existing subway tunnel 1-2 months before formal construction of a jacking pipe, the arrangement range of deformation monitoring sections of the existing subway tunnel is 60m away from the left side and the right side of a plane intersection point of a new tunnel and an old tunnel, the arrangement intervals are arranged according to 5m, 10m and 20m from two sides of a jacking pipe jacking axis, 5 prisms are arranged in each section, the prism A is used for monitoring vertical displacement of a vault of the tunnel, the prisms B and C are used for monitoring clearance and convergence of the tunnel, the prism D is used for monitoring horizontal displacement of a track bed, the prism E is used for monitoring vertical displacement of the track bed, and the arrangement of the deformation monitoring points of the tunnel section is shown in figure 2.
Step two, calculating the excavation influence range
The influence degree of the rectangular pipe jacking construction on the existing tunnel dynamically changes along with the tunneling distance of an excavation face, the influence range of excavation is calculated by combining engineering data and a theoretical method before pipe jacking excavation, the existing tunnel is regarded as a Timoshenko beam model placed on a Pastnak foundation, and the calculation model of the influence range of excavation is shown in figure 3. The method comprises the following steps of calculating a change graph of the maximum uplift value of the existing tunnel along with the excavation distance by adopting a Mindlin solution and a finite difference method, setting an interval with no obvious change of the uplift value as a secondary influence area, and setting an interval with obvious change as a primary influence area, wherein the detailed calculation process can refer to the literature: liang R, kang C, xing L, li Z, lin C, gao K, guo Y,2021.Responses of in-service shift to overlapping in-soft ground. Environmental Earth sciences.80 (5), 1-15. The theory and a large number of actual measurement results show that the excavation face is a primary influence area within a range of 3 times the width of the newly-built jacking pipe from the axis of the existing tunnel, a secondary influence area outside the range of 3 times the width of the newly-built jacking pipe, and the excavation primary influence area of the newly-built tunnel is shown in fig. 4.
Step three, the pipe jacking machine enters the hole
And after finishing measurement and lofting, installing a frame, a backrest and a main jacking device of the pipe jacking machine, debugging equipment, breaking a tunnel door and the like, and operating the pipe jacking machine to enter the tunnel.
Step four, hoisting the cushion block and the pipe joint
After the jacking jack jacks a pipe joint, the cushion block and the pipe joint are timely hoisted, and a new pipe joint is installed.
Step five, jacking and measuring the jacking pipe
The jacking speed v of the jacking pipe is controlled to be 3.5-4 m/d in the secondary influence area obtained by calculation in the step two, the jacking force F is controlled to be 2-3 m/d in the primary influence area, the jacking force F is calculated according to the formula (1) by combining with the engineering condition, and other construction parameters need to be dynamically adjusted according to ground surface and tunnel deformation feedback data continuously to achieve the optimal state.
And closely controlling the jacking axis in the jacking process, measuring the posture of the machine head after the jacking of each pipe joint is finished, and immediately carrying out correction by taking measures such as cutter head reversal, pressing iron and the like once a small corner appears in the machine head. The pipe jacking machine adopts the form of a spiral conveyor, a track soil box, a winch and a crawler crane to excavate soil. In the jacking process, the soil output of each section is counted as accurately as possible, the soil output is strived to keep consistent with the theoretical soil output, overexcavation or underexcavation is avoided, the relative stability of a front soil body is ensured, and disturbance to the stratum is reduced. The jacking distance of the jacking pipe is closely monitored through a total station behind an originating well in the jacking process of the jacking pipe, the jacking distance is recorded and compared with an excavation influence range, the frequency of monitoring the jacking distance is gradually increased along with the continuous excavation of the jacking pipe, 1-2 times in a secondary influence area are measured for 1 day, and 3-4 times in a main influence area are measured for 1 day, so that the influence area where the excavation surface of the jacking pipe is located is timely judged.
Step six, pressing and injecting soil consolidation slurry
When the jacking pipe is jacked in, the consolidation slurry is timely injected through the pipe wall grouting hole in a pressing mode, so that the slurry permeates into a soil layer around the jacking pipe and is hardened in the soil layer, and the effect of reinforcing the soil layer is achieved. Grouting sequence: ground mixing → start of the mud pump → opening of the valve of the main pipe → opening of the valve of the pipe joint → mud feeding → closing of the valve of the pipe joint → closing of the valve of the main pipe → disassembly of the quick joint in the well → connection of the lower pipe joint → connection of the 2 inch main pipe → the cycle is repeated. Grouting materials and proportioning: the cementing material adopts P042.5 cement, the proper slurry proportion can improve the diffusion and reinforcement range of the slurry and control the gelation time of the slurry, and the slurry proportion is controlled in the following range: 0.5.
Step seven, existing tunnel deformation monitoring
Monitoring the deformation of the existing shield tunnel by using an intelligent total station in the jacking process of the jacking pipe; when the excavation surface of the jacking pipe is in the secondary influence area, the monitoring frequency is 1-2 times/day, and when the excavation surface of the jacking pipe is in the main influence area, the monitoring frequency is 3-4 times/day.
Step eight, judging the maximum uplift value of the tunnel
Before the excavation face enters a main influence area, if the monitored vertical displacement value of the maximum vault of the existing tunnel is smaller than a set early warning value, the set range of the early warning value is 3-5 mm (in the embodiment, the early warning value is set to be 3 mm), ballast measures do not need to be taken for the pipe joints, and whether the ballast measures are taken or not is determined according to whether the monitored vertical displacement value of the maximum vault of the existing tunnel is larger than or equal to the set early warning value or not in the pipe-jacking tunneling process. If no ballast measures are needed, repeating the fourth step to the seventh step until the ten-step pipe jacking machine goes out of the tunnel.
Step nine, stacking the ballast weight
When the pipe jacking excavation surface enters a main influence area or in a subsequent tunneling process, if the monitored vertical displacement value of the maximum vault of the existing tunnel is larger than or equal to a set early warning value, ballast measures need to be taken for the pipe joints. If the heaping is carried out before the pipe jacking excavation surface enters the main influence area, the weight difference between the excavated soil body and the pipe joints is calculated in time after the pipe jacking machine excavates the capacity of one pipe joint for the soil body in front of the tunnel each time, and the heaping load and the pressure weight are carried out on the pipe joints in the main influence area by adopting prefabricated C20 plain concrete or iron blocks with the same weight difference weight. In order to facilitate later-stage transportation, the plain concrete is layered and partitioned by nine clamping plates, the size of each block is 1m multiplied by 4m multiplied by 0.5m, the plain concrete is transported out by matching with a pulley trolley and a crane in the later stage, and the plain concrete is arranged on two sides in the pipe joint rail, so that the passage of the pulley trolley is prevented from being influenced. After the soil body of each pipe joint is excavated until the pile loading and the weight are finished, the subsequent excavation work of the soil body can be carried out. When a ballasted pipe section leaves the primary zone of influence, it should be used to lift off ballasted plain concrete or iron blocks onto a pipe section that subsequently enters the primary zone of influence. If the piling loading is carried out in the subsequent tunneling process, all the pipe joints in the main influence area are immediately piled, and the steps are consistent with the steps.
Step ten, the pipe jacking machine goes out of the hole
If no ballast measures are taken in the jacking process of the jacking pipe, the jacking pipe machine is decomposed and hoisted out of the receiving well, then slurry replacement is carried out, and the treatment of pipe equipment dismantling, caulking, cleaning and joint treatment is carried out.
Eleven steps of soil body reinforcement of main influence area
If ballast measures are taken for the jacking pipe, grouting reinforcement is carried out on the soil layer in the main influence area through the pipe joint grouting hole after the jacking pipe is completely communicated.
Step twelve, moving out the stacked objects
And after grouting reinforcement, removing the stacked objects section by section, synchronously monitoring the deformation of the existing tunnel, if the deformation of the existing tunnel is stable after each section of stacked object is removed, continuously removing the next section of stacked object until all the stacked objects are removed, and if the deformation is unstable, continuously grouting or taking other stratum reinforcement measures until the subsequent deformation of the tunnel is not influenced by removing the heavy objects. And after the tunnel is deformed and stabilized, performing subsequent work after the pipe jacking machine is lifted out of the receiving well in the step ten.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above embodiments, and all technical solutions that belong to the idea of the present invention belong to the scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims (10)

1. An unloading balance construction method for a newly-built rectangular pipe jacking upward-penetrating existing subway tunnel is characterized by comprising the following steps:
s1, arranging existing tunnel deformation monitoring points;
s2, calculating an excavation influence range, and regarding the existing tunnel as a Timoshenko beam model placed on a Pasternak foundation to obtain a main range of influence of longitudinal deformation of the existing tunnel on a newly built pipe-jacking tunnel;
s3, measuring and lofting, installing a push bench frame, a backrest and a main jacking device, debugging equipment and entering a hole by the push bench;
s4, hoisting the cushion block and the pipe joint;
s5, jacking and measuring the jacking pipe;
s6, pressing and injecting soil consolidation slurry, wherein the consolidation slurry is timely pressed and injected through a pipe wall grouting hole when the jacking pipe is jacked in, so that the slurry permeates into a soil layer around the jacking pipe and is hardened in the soil layer, and the soil layer is reinforced;
s7, monitoring the deformation of the existing tunnel;
s8, judging the maximum crown value of the tunnel, if the monitored vertical displacement value of the maximum vault of the existing tunnel is smaller than a set early warning value before the excavated surface enters a main influence area, not taking ballast measures for the pipe joints, and subsequently determining whether ballast measures are taken according to whether the monitored vertical displacement value of the maximum vault of the existing tunnel is larger than or equal to the set early warning value in the process of pipe-jacking tunneling; if no ballast measures are taken, repeating the steps S4-S7 until the pipe jacking machine goes out of the hole in the step S10;
s9, carrying out ballast weight, and taking ballast measures on the pipe joints if the monitored vertical displacement value of the maximum vault of the existing tunnel is larger than or equal to a set early warning value before the excavation face enters a main influence area or in the subsequent excavation process;
and S10, after the machine head reaches the receiving well, the pipe jacking machine goes out of the hole.
2. The unloading balance construction method for the newly-built rectangular top pipe to pass through the existing subway tunnel according to claim 1, wherein the step S1 specifically comprises: arranging deformation monitoring points on an existing subway tunnel 1-2 months before the formal construction of a jacking pipe, wherein the arrangement range of deformation monitoring sections of the existing subway tunnel is 60m away from the left side and the right side of the intersection point of the plane of a new tunnel and an old tunnel, the arrangement intervals are arranged according to 5m, 10m and 20m from the two sides of the jacking axis of the jacking pipe, and 5 prisms are arranged in all sections, wherein the first prism is arranged at the topmost part of the center of each section and is used for monitoring the vertical displacement of the vault of the tunnel; the second prism and the third prism are arranged at two ends of the horizontal axis of the section and are used for monitoring the clearance convergence of the tunnel; the fourth prism and the fifth prism are respectively arranged on the track bed and are respectively used for monitoring the horizontal displacement and the vertical displacement of the track bed.
3. The unloading balance construction method for the newly-built rectangular top pipe to pass through the existing subway tunnel according to claim 1, wherein the step S2 specifically comprises: the method comprises the following steps of calculating a change graph of the maximum uplift value of the existing tunnel along with the excavation distance by adopting a Mindlin solution and a finite difference method, setting an interval with no obvious change of the uplift value as a secondary influence area, and setting an interval with obvious change as a primary influence area, wherein the change graph specifically comprises the following steps: the excavation surface is a primary influence area within 3 times of the width range of the newly built jacking pipe from the existing tunnel axis, and a secondary influence area outside the 3 times of the width range of the newly built jacking pipe.
4. The unloading balance construction method for the newly-built rectangular pipe jacking upward-penetrating existing subway tunnel according to claim 1, wherein the pipe jacking machine entering in the step S3 specifically comprises the following steps: after the measurement and lofting are finished, installing a frame, a backrest and a main jacking device of the pipe jacking machine, debugging equipment, and operating the pipe jacking machine to enter a hole after the hole breaking door works; the hoisting cushion block and the pipe joint are specifically as follows: after the jacking jack jacks a pipe joint, the cushion block and the pipe joint are timely hoisted, and a new pipe joint is installed.
5. The unloading balance construction method for the newly-built rectangular pipe jacking upward-penetrating existing subway tunnel according to claim 1, wherein the step S5 of pipe jacking and measuring specifically comprises the following steps:
the jacking speed v of the jacking pipe is controlled to be 3.5-4 m/d in the secondary influence area obtained by calculation in the step two, the jacking force F is controlled to be 2-3 m/d in the primary influence area, the jacking force F is calculated according to the formula (1) by combining with the engineering condition, and other construction parameters need to be dynamically adjusted according to the deformation feedback data of the earth surface and the tunnel continuously to achieve the optimal state:
F＝F 1 +F 2 (1)
in the formula: f is the minimum jacking force in kN; f 1 Unit kN, F for the frictional resistance between the pipeline and the soil layer 1 L is the jacking length of the jacking pipe and the unit is m; f is the average frictional resistance between the outer wall of the pipeline and the soil, and the unit kN/m 2 Preferably 7 to 12kN/m 2 ；F 2 Is the head-on resistance of the push bench in kN, F 2 ＝a×bR 1 ，R 1 The passive earth pressure at 1/3 of the lower part of the push bench is expressed in kN; a is the width of the push bench in m; and b is the height of the push bench in m.
6. The unloading balance construction method for the newly-built rectangular top pipe to pass through the existing subway tunnel according to claim 1, wherein the grouting sequence of the soil consolidation grout injected under pressure in the step S6 is specifically as follows: mixing slurry on the ground → starting a slurry pressing pump → opening a main pipe valve → opening a pipe joint valve → delivering slurry → closing the pipe joint valve → closing the main pipe valve → disassembling a quick joint in the well → descending a pipe joint → connecting a 2-inch main pipe → repeating the cycle; grouting materials and proportioning: the cementing material adopts P042.5 cement, and the slurry proportion is controlled in the following range: 0.5.
7. The unloading balance construction method for the newly-built rectangular pipe jacking upward-penetrating existing subway tunnel according to claim 1, wherein the step S7 of monitoring the deformation of the existing tunnel specifically comprises the following steps: in the jacking process of the jacking pipe, monitoring the deformation of the existing shield tunnel by using an intelligent total station; when the excavation surface of the jacking pipe is in a secondary influence area, monitoring frequency is 1-2 times/day; when the excavation surface of the jacking pipe is in a main influence area, the monitoring frequency is 3-4 times/day.
8. The unloading balance construction method for the newly-built rectangular pipe jacking upward-going existing subway tunnel according to claim 1, wherein the setting range of the early warning value in the step S8 and the step S9 is 3-5 mm.
9. The unloading balance construction method for the newly-built rectangular pipe jacking upward-crossing existing subway tunnel according to claim 1, wherein the concrete steps of taking ballast measures for the pipe joints in the step S9 are as follows:
s91, if the heaping load is carried out before the pipe jacking excavation surface enters the main influence area, after the capacity of a pipe joint is excavated on the soil body in front of the tunnel by the pipe jacking machine each time, the weight difference between the excavated soil body and the pipe joint is calculated in time, and the heaping load is carried out on the pipe joint in the main influence area by adopting prefabricated C20 plain concrete or iron blocks with the same weight difference; (ii) a After the soil body of each pipe joint is excavated until the pile loading weight is finished, carrying out subsequent soil body excavation work; when the ballasted pipe joint leaves the main influence area, the ballasted plain concrete or iron blocks are moved away to the pipe joint which subsequently enters the main influence area;
and S92, if the pile loading is carried out in the subsequent tunneling process, immediately carrying out pile loading and weight pressing on all pipe joints in the main influence area, wherein the specific steps are consistent with the step S91.
10. The unloading balance construction method for the newly-built rectangular pipe jacking upward-penetrating existing subway tunnel according to claim 1, wherein the step S10 of pipe jacking machine hole exiting specifically comprises two conditions:
s101, if ballast measures are not taken in the whole jacking process of the jacking pipe, the jacking pipe is decomposed and hoisted out of a receiving well, then slurry replacement is carried out, and the treatment of pipe internal equipment, caulking, cleaning and joint treatment is carried out;
s102, if ballast measures are taken for the jacking pipe, grouting and reinforcing a soil layer in a main influence area through a pipe joint grouting hole after the jacking pipe is completely communicated; after grouting reinforcement, removing the stacked objects section by section, synchronously monitoring the deformation of the existing tunnel, if the deformation of the existing tunnel is stable after each section of stacked object is removed, continuously removing the next section of heavy object until all the stacked objects are removed, and if the deformation is unstable, continuously grouting or adopting other stratum reinforcement measures until the removed stacked object does not influence the subsequent deformation of the tunnel; and after the tunnel is deformed stably, the pipe jacking machine is disassembled, and the receiving well is hoisted out and then works.
CN202210774164.4A 2022-07-01 2022-07-01 Unloading balance construction method for newly-built rectangular pipe-jacking upward-penetrating existing subway tunnel Pending CN115306397A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116878577A (en) * 2023-07-19 2023-10-13 山东大学 Method and system for monitoring tunnel drilling and blasting in-situ reconstruction and expansion engineering

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116878577A (en) * 2023-07-19 2023-10-13 山东大学 Method and system for monitoring tunnel drilling and blasting in-situ reconstruction and expansion engineering
CN116878577B (en) * 2023-07-19 2024-02-27 山东大学 Method and system for monitoring tunnel drilling and blasting in-situ reconstruction and expansion engineering

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