Starting and receiving construction method for slurry balance jacking pipe in water-rich unconsolidated formation

Abstract

The invention discloses a water-rich unconsolidated formation slurry balance pipe jacking starting and receiving construction method, and relates to the technical field of trenchless underground pipeline construction, which comprises the following steps: adopting a combined process of TRD groove wall U-shaped reinforcement, three-axis mixing pile construction, high-pressure jet grouting pile joint filling, precipitation treatment and WSS grouting water stop to reinforce an end, additionally arranging a circular steel ring outside a concrete hole door, two elastic steel plates are additionally arranged in the circular steel ring, a sponge block is filled between the two elastic steel plates, and starting tunneling control, receiving tunneling control and tunnel portal blocking are conducted; according to the TRD groove wall U-shaped reinforcement, three-axis stirring pile construction, high-pressure jet grouting pile seam filling, precipitation treatment and WSS grouting water stop technology, the problem of water and sand gushing of the tunnel portal caused by reinforcement body cracking can be effectively solved, the problems that due to pipe jacking starting receiving, a pipeline is damaged, rainwater and sewage enter the stratum, and the end area severely settles and water and sand gushing of the tunnel portal are caused can be solved, and the construction efficiency is improved. The sponge block can improve the water stopping effect between the two elastic steel plates, and water and soil are effectively prevented from gushing out.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of trenchless underground pipeline construction, and particularly relates to a mud balance pipe jacking launching and receiving construction method in water-rich loose stratum. BACKGROUND

[0002] Pipe jacking launching and receiving construction refers to the process of pushing a pipe jacking machine through the soil layer from a working pit (launching well) to a receiving pit (arrival well). With the development of society and progress of the times, pipe jacking construction has become very common. However, in water-rich soft soil stratum, because of poor end reinforcement effect, poor sealing of the hole portal, and other problems, water and sand gushing from the hole portal, ground subsidence, pipeline rupture, and other dangerous situations often occur. Even if measures are taken in a timely and appropriate manner after a dangerous situation occurs, accidents can still easily occur.

[0003] In the mud balance pipe jacking construction in water-rich loose stratum, water and sand gushing from the hole portal, ground subsidence, pipeline rupture, and other dangerous situations are easily caused by poor end reinforcement effect, sealing failure of the hole portal, and other problems. At present, the end reinforcement scheme mainly adopts a combination of triaxial mixing + rotary jet grouting pile joint filling + dewatering, which is affected by confined water and has poor integrity of the reinforced body. The hole portal sealing mainly adopts a combination of ordinary cord rubber plate + folding plate, which is easily caused to fail by attitude deviation of the pipe jacking machine. In addition, insufficient pipeline protection measures also exacerbate the construction risk. Therefore, the present application proposes a mud balance pipe jacking launching and receiving construction method in water-rich loose stratum to solve the problems in the prior art. SUMMARY

[0004] The present application aims to provide a mud balance pipe jacking launching and receiving construction method in water-rich loose stratum, which uses a combination process of TRD slot wall U-shaped reinforcement + triaxial mixing pile construction + high-pressure rotary jet grouting pile joint filling + dewatering treatment + WSS grouting water stop to reinforce the launching and receiving end of the pipe jacking, thereby preventing water and sand gushing from the hole portal caused by cracking of the reinforced body.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0006] The mud balance pipe jacking launching and receiving construction method in water-rich loose stratum comprises the following steps:

[0007] Step 1: End reinforcement, a combination process of TRD slot wall U-shaped reinforcement + triaxial mixing pile construction + high-pressure rotary jet grouting pile joint filling + dewatering treatment + WSS grouting water stop is used to reinforce the launching and receiving end of the pipe jacking;

[0008] Step 2: Hole portal sealing device installation, a circular steel ring is added outside the concrete hole portal, then two elastic steel plates are added inside the circular steel ring of the hole portal cord, and sponge blocks are filled between the two elastic steel plates;

[0009] Step three: the original excavation control, pipe jacking machine in the reinforcement area with low speed, low thrust, low bin pressure, after the pipe jacking machine enters the curtain cloth and the cutter head is not out of the reinforcement area, the hole sealing grouting construction is carried out;

[0010] Step four: receiving excavation control, when the pipe jacking machine is 30m away from the end of the reinforcement, the attitude is retested and adjusted to the axis deviation less than 30mm, the pipe jacking machine enters the reinforcement body with low thrust, before the pipe jacking machine enters the reinforcement body and is not received, the hole is opened in the edge ring pipe for secondary grouting, the pressure test is carried out before breaking through the reinforcement body, and the cutter head stops rotating after breaking through the reinforcement body at low speed.

[0011] Step five: hole sealing, after the pipe jacking receiving is completed, the pipe hole is subjected to secondary grouting construction and verification of double liquid slurry, the curtain cloth is removed after the grouting effect is verified, the gap between the circular steel ring at the hole is sealed with quick-drying cement, and the sealing steel plate is installed and welded.

[0012] Further improvement lies in that when the TRD slot wall U-shaped reinforcement process is used for reinforcement construction of the pipe jacking starting and receiving end in step one, specifically including: treating poor geology and obstacles before construction, laying steel plates to reinforce the site, and monitoring the wall perpendicularity in real time through the while-drilling inclinometer during construction to ensure that the overlapping length of adjacent TRD walls is greater than 50cm, and the grouting pump flow is adjusted when the cutting box is pulled out to avoid foundation settlement.

[0013] Further improvement lies in that when the triaxial mixing pile construction process is used for reinforcement construction of the pipe jacking starting and receiving end in step one, specifically including: after the construction site is leveled, the pile position is marked with a total station instrument, the positioning error is controlled within ±50mm; the cement slurry is prepared according to the mixing ratio, the jet grouting machine is started, the jet grouting machine slowly sinks along the guide frame from top to bottom, the slurry is sprayed while rotating during pre-mixing sinking, the in-situ grouting is performed for 30 seconds after sinking to the pile bottom, the jet grouting is mixed to the design elevation of the pile top, and the in-situ grouting is performed for 30 seconds, and the up-down mixing is repeated once.

[0014] Further improvement lies in that when the high-pressure rotary jet grouting pile joint repair process is used for reinforcement construction of the pipe jacking starting and receiving end in step one, specifically including: positioning the rotary jet grouting pile machine, then preparing the cement slurry, sinking the jet grouting pipe to the designed depth, keeping the rotary state, increasing the pressure of the high-pressure slurry pump to the construction design value, then jet grouting for 30 seconds at the pile bottom position, then jet grouting, rotation and lifting the drill pipe at the preset speed, until the jet grouting pipe is lifted to the stop grouting surface.

[0015] Further improvement lies in that when the dewatering treatment process is used for reinforcement construction of the pipe jacking starting and receiving end in step one, specifically including: adjusting the distance between the dewatering well and the underground continuous wall, and setting the dewatering well closer to the continuous wall.

[0016] Further improvement lies in that: when the WSS grouting water-stopping process is used for reinforcing construction of the pipe jacking starting and receiving end, the method comprises the following steps: proportioning non-shrinkage grouting liquid, then designing grouting pressure according to hydrostatic pressure, and finally selecting pressure coefficient K according to grouting depth, when the depth is less than 8m, the value of K is 0.023-0.021, the drilling deviation is controlled within ±3cm, the incidence angle deviation is less than or equal to 1°, and the grouting sequence is from outside to inside and interval construction.

[0017] Further improvement lies in that: in the second step, the circular steel ring is rolled from 10mm thick steel plate, and the rubber cord plate and two elastic steel plates are brush-welded on the circular steel ring, the thickness of the elastic steel plate is 3-5mm, and the compression rate of the sponge block is greater than 30%.

[0018] Further improvement lies in that: in the third step, in the starting excavation, the pipe jacking machine advances at a speed of less than or equal to 20mm / min in the reinforced area, the thrust is less than or equal to 1000kN, the warehouse pressure is controlled to be 0.02-0.05MPa, before the cutter head of the pipe jacking machine rotates, the distance L1 from the hole portal to the innermost elastic steel plate is measured first, then the length L2 of the L1 elastic steel plate is summed to obtain the value of L 总 , and when the cutter head of the pipe jacking machine enters, the cutter head cutout ring is greater than the value of L 总 , and then the cutter head rotates.

[0019] Further improvement lies in that: in the fourth step, in the receiving excavation, the warehouse pressure is reduced to 0, and it is ensured that there is no pressure increase within 30 minutes after the warehouse pressure is reduced to 0.

[0020] Further improvement lies in that: in the fifth step, the blocking plate is a processed steel ring, the processed steel ring is welded and fixed with the circular steel ring at the hole portal, and a diagonal brace is punched at the rear part for reinforcement.

[0021] The beneficial effects of the present application are:

[0022] The method adopts the combined process of TRD slot wall U-shaped reinforcement, triaxial mixing pile construction, high-pressure rotary jet grouting pile joint filling, dewatering treatment and WSS grouting water-stopping to reinforce the pipe jacking starting and receiving end, effectively prevents the hole portal water and sand gushing caused by cracking of the reinforcement, improves the reinforcement effect and construction quality, and the WSS grouting technology can also avoid the problems of rainwater and sewage entering the stratum due to damage of the pipe jacking starting and receiving, causing serious settlement of the end area and water and sand gushing of the hole portal.

[0023] The present application adds a circular steel ring outside the concrete hole portal, then adds two elastic steel plates inside the circular steel ring of the hole portal curtain cloth, and fills sponge blocks between the two elastic steel plates, so that the water-stopping effect between the two elastic steel plates is improved, water and soil can be effectively prevented from gushing when the curtain cloth and the pressing plate fail, the safety of pipe jacking construction is ensured, and the construction efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0025] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0026] according to Figure 1 As shown, this embodiment proposes a construction method for starting and receiving slurry-water balanced pipe jacking in a water-loose formation, including the following steps:

[0027] Step 1: End reinforcement: Use the combined technology of TRD trench wall U-shaped reinforcement + three-axis mixing pile construction + high-pressure rotary jet pile filling + dewatering treatment + WSS grouting and water-stopping to reinforce the starting and receiving ends of the jacking pipe.

[0028] The TRD trench wall U-shaped reinforcement process is used to reinforce the starting and receiving ends of the jacking pipe. Specifically, it includes: dealing with unfavorable geological conditions and obstacles before construction, laying steel plates to reinforce the site, using a drilling inclinometer to monitor the verticality of the wall in real time during construction to ensure that the overlap length of adjacent TRD walls is greater than 50cm, and adjusting the grouting pump flow when pulling out the cutting box to avoid foundation settlement.

[0029] When using the three-axis mixing pile construction process to reinforce the starting and receiving ends of the jacking pipe, it specifically includes: after the construction site is leveled, the pile position is calibrated with a total station to control the positioning error within ±50mm; cement slurry is prepared according to the mix ratio, and the shotcrete machine is started, so that the shotcrete machine slowly cuts the soil from top to bottom along the guide frame, and rotates while spraying during pre-mixing and sinking. After sinking to the bottom of the pile, spray in situ for ≥30 seconds, and then lift the spraying and mixing to the design elevation of the pile top and spray in situ for 30 seconds, and repeat the up and down mixing once.

[0030] When using the high-pressure rotary jet pile filling process to reinforce the starting and receiving ends of the jacking pipe, the process specifically includes: positioning the rotary jet pile machine, then preparing cement slurry, after the grouting pipe sinks to the designed depth, keep rotating, and at the same time increase the pressure of the high-pressure mud pump to the construction design value, and then sit at the bottom of the pile and spray for 30 seconds, then continue spraying, rotating, and lifting the drill rod at a preset speed until the grouting pipe is lifted to the grouting stop surface.

[0031] When using the dewatering treatment process to reinforce the starting and receiving ends of the jacking pipe, it specifically includes: adjusting the distance between the dewatering well and the underground continuous wall, and setting the dewatering well closer to the continuous wall.

[0032] The WSS grouting water stopping process is adopted to reinforce the starting and receiving end of pipe jacking, which specifically includes: proportionally preparing non-shrinkage grouting liquid, then designing grouting pressure according to hydrostatic pressure, and finally selecting pressure coefficient K according to grouting depth, when the depth is less than 8 m, the value of K is 0.023-0.021, the drilling deviation is controlled within ±3 cm, the incidence angle deviation is less than or equal to 1°, the grouting sequence is from outside to inside, and interval construction, the grouting pressure (final pressure value) is 2-3 times of the hydrostatic pressure, and the maximum can reach 3-5 times. According to the grouting depth, P=KH is calculated, wherein: P is the design grouting pressure (final pressure value) (Mpa); H is the grouting depth (m); and K is the pressure coefficient determined by the grouting depth;

[0033] In the embodiment, the value of pressure coefficient K is as shown in the following table:

[0034]

[0035] In the embodiment, the non-shrinkage grouting liquid is divided into three types of super-high strength type CW-3A, high strength type CW-313 and ordinary type CW-3C, and the standard proportioning of the grouting liquid is shown in the following table:

[0036] Properties of standard grouting liquid

[0037]

[0038] Standard proportioning of non-shrinkage grouting liquid

[0039]

[0040] The specific grouting control points are as follows:

[0041] Fixed hole position: according to the design requirements, align the hole position, drill at different incidence angles, and the hole position deviation is required to be ±3 cm, and the incidence angle deviation is not greater than 1°.

[0042] Drilling machine in position: the drilling machine is positioned according to the specified position, and the verticality of the drill rod is adjusted. After aligning the drilling hole, the drilling machine shall not be moved, and shall not be raised and lowered at will.

[0043] Drilling machine hole forming: during construction, slow operation is required, the influence of the stratum on the drilling machine is mastered to determine the drilling coefficient under the stratum condition. The overflow and outflow conditions are closely observed, and when a large amount of overflow and outflow occurs, the drilling should be stopped immediately, and the construction is carried out after analyzing the reasons. After drilling a section, check a section, correct deviation in time, and the empty bottom position should be less than 30 cm. The drilling and grouting sequence is from outside to inside, and the interval construction is carried out between the holes in the same circle.

[0044] Drill rod retraction: strictly control the lifting amplitude, uniformly retract, and pay attention to the change of grouting parameters.

[0045] Grouting: The diameter of the grouting hole should be no less than 45mm. Strictly control the grouting pressure and pay close attention to the grouting volume. If the pressure suddenly rises or grout overflows from the hole wall or cross-section, stop grouting immediately. After identifying the cause, adjust the grouting parameters or shift the hole, then restart grouting. If the soil layer is prone to collapse, use forward grouting; otherwise, use backward grouting.

[0046] Step 2: Install the portal sealing device. Add a circular steel ring outside the concrete portal, then add two elastic steel plates inside the circular steel ring on the inner side of the portal curtain, and fill sponge blocks between the two elastic steel plates; the circular steel ring is rolled with 10mm thick steel plate, the curtain rubber plate and the two elastic steel plates are brush-welded to the circular steel ring, the thickness of the elastic steel plate is 3-5mm, and the compression rate of the sponge block is greater than 30%.

[0047] Step 3: Initial excavation advance control, the pipe jacking machine advances in the reinforcement area at low speed, low thrust, and low chamber pressure. After the pipe jacking machine has fully entered the curtain and before the cutterhead has left the reinforcement area, the tunnel door sealing ring grouting construction is carried out; the pipe jacking machine advances in the reinforcement area at a speed of ≤20mm / min, the thrust ≤1000kN, and the chamber pressure is controlled at 0.02-0.05MPa. Before the cutterhead of the pipe jacking machine rotates, first measure the distance L1 from the tunnel door to the innermost elastic steel plate, and then sum the length L2 of the elastic steel plate L1 to obtain L 总 When the cutter head of the pipe jacking machine enters, ensure that the cutter head ring is larger than L 总 value, and then rotate the cutter head.

[0048] Step 4: Accept the excavation control, re-measure the posture when the pipe jacking machine is 30m away from the end reinforcement body and adjust it to an axis deviation of less than 30mm, and advance it with low thrust after the pipe jacking machine enters the reinforcement body. Before the pipe jacking machine enters the reinforcement body and is not accepted, open a hole in the edge ring pipe for secondary grouting, and conduct a pressure reduction test before penetrating the reinforcement body. The cutterhead stops rotating after penetrating the reinforcement body at a low speed. During the pressure reduction test, ensure that there is no pressurization within 30 minutes after the chamber pressure drops to 0.

[0049] Step 5: Tunnel portal sealing. After the jacking pipe is received, the pipe hole is subjected to double-liquid slurry secondary grouting construction and verification. After verifying the grouting effect, the curtain is removed, and the gap between the circular steel ring at the tunnel portal is sealed with quick-drying cement. The sealing steel plate is installed and welded fixed; the sealing plate is a processed steel ring, which is welded and fixed to the circular steel ring at the tunnel portal, and a diagonal brace is added at the rear for reinforcement.

[0050] The beneficial effects of the present invention are:

[0051] The method of the present application adopts the combined process of TRD groove wall U-shaped reinforcement + triaxial mixing pile construction + high-pressure rotary jet grouting pile joint filling + dewatering treatment + WSS grouting water stop to reinforce the starting and receiving end of the pipe jacking, effectively prevents the hole door gushing water and sand caused by the cracking of the reinforcement, improves the reinforcement effect and construction quality, and the WSS grouting technology can also avoid the damage of the pipe jacking starting and receiving to the pipeline, so that rainwater and sewage enter the stratum, causing serious settlement of the end area and hole door gushing water and sand. The present application adds a circular steel ring outside the concrete hole door, then adds two elastic steel plates inside the circular steel ring of the hole door curtain, and fills sponge blocks between the two elastic steel plates, which can improve the water stop effect between the two elastic steel plates, effectively prevent water and soil from gushing out when the curtain and pressing plate fail, and ensure the safety of pipe jacking construction and improve the construction efficiency.

[0052] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. The method for launching and receiving mud-water balanced pipe jacking in water-rich loose formations is characterized by: The following steps are involved: Step 1: End reinforcement: Use the combined process of TRD trench wall U-shaped reinforcement + triaxial mixing pile construction + high-pressure jet grouting pile filling + dewatering treatment + WSS grouting waterstop to reinforce the starting and receiving ends of the jacking pipe; Step 2: Install the portal sealing device. Add a circular steel ring outside the concrete portal, then add two elastic steel plates inside the circular steel ring inside the portal curtain, and fill the space between the two elastic steel plates with sponge blocks. Step 3: Initial excavation advance control: the pipe jacking machine is advanced in the reinforcement area at low speed, low thrust, and low chamber pressure. After the pipe jacking machine has fully entered the curtain and before the cutterhead has left the reinforcement area, the tunnel gate sealing ring grouting construction is carried out; Step 4: Take over the tunneling control. When the jacking machine is 30m away from the end reinforcement, re-measure the posture and adjust it to an axis deviation of less than 30mm. After the jacking machine enters the reinforcement, advance it with low thrust. Before the jacking machine fully enters the reinforcement and is not accepted, open a hole in the edge ring pipe for secondary grouting. Before penetrating the reinforcement, perform a pressure reduction test. The cutterhead stops rotating at a low speed after penetrating the reinforcement. Step 5: Tunnel portal sealing. After the jacking pipe is received, the pipe hole is subjected to double-liquid slurry secondary grouting construction and verification. After verifying the grouting effect, the curtain is removed, and the gap between the circular steel ring at the tunnel portal is sealed with quick-drying cement. The sealing steel plate is installed and welded fixed.

2. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose formations according to claim 1 is characterized by: When the U-shaped reinforcement process of the TRD trench wall is used to reinforce the starting and receiving ends of the jacking pipe in step 1, the following steps are specifically performed: treating unfavorable geology and obstacles before construction, laying steel plates to reinforce the site, monitoring the verticality of the wall in real time through a while-drilling inclinometer during construction to ensure that the overlap length of adjacent TRD walls is greater than 50 cm, and adjusting the grouting pump flow rate when pulling out the cutting box to avoid foundation settlement.

3. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose formations according to claim 1 is characterized by: When the three-axis mixing pile construction process is used in the step 1 to reinforce the starting and receiving ends of the jacking pipe, the following steps are specifically included: after the construction site is leveled, the pile position is calibrated using a total station to control the positioning error within ±50mm; cement slurry is prepared according to the mix ratio, and the shotcrete machine is started, so that the shotcrete machine slowly cuts the soil from top to bottom along the guide frame, and rotates while spraying during pre-stirring and sinking. After sinking to the bottom of the pile, the slurry is sprayed in situ for ≥30 seconds. After the slurry is lifted and stirred to the designed elevation of the pile top, the slurry is sprayed in situ for 30 seconds, and the mixing is repeated up and down once.

4. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized in that: When the high-pressure rotary jet pile filling process is used to reinforce the starting and receiving ends of the jacking pipe in the step one, the process specifically includes: positioning the rotary jet pile machine, then preparing cement slurry, after the grouting pipe sinks to the designed depth, keeping it in a rotating state, and at the same time increasing the pressure of the high-pressure mud pump to the construction design value, and then spraying at the bottom of the pile for 30 seconds, and then spraying, rotating, and lifting the drill rod at a preset speed until the grouting pipe is lifted to the grouting stop surface.

5. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized in that: When the dewatering treatment process is used in the step 1 to reinforce the starting and receiving ends of the jacking pipe, it specifically includes: adjusting the distance between the dewatering well and the underground continuous wall, and setting the dewatering well at a position closer to the continuous wall.

6. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized in that: When the WSS grouting and water-stopping technology is used to reinforce the starting and receiving ends of the jacking pipe in step 1, it specifically includes: preparing non-shrinkage grouting liquid in proportion, then designing the grouting pressure according to the hydrostatic pressure, and finally selecting the pressure coefficient K according to the grouting depth. When the depth is less than 8m, the value of K is 0.023-0.

021. During grouting, the drilling deviation is controlled within ±3cm, the incident angle deviation is ≤1°, and the grouting sequence is from outside to inside and the construction is carried out at intervals.

7. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized by: In the step 2, the circular steel ring is rolled with a 10 mm thick steel plate, the cord rubber sheet and two elastic steel plate brushes are welded to the circular steel ring, the thickness of the elastic steel plate is 3-5 mm, and the compression rate of the sponge block is greater than 30%.

8. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized in that: During the excavation in step 3, the jacking machine advances at a speed of ≤20mm / min in the reinforcement area, the thrust is ≤1000kN, and the bin pressure is controlled at 0.02-0.05MPa. Before the cutter head of the jacking machine rotates, the distance L1 from the tunnel entrance to the innermost elastic steel plate is first measured, and then the length L2 of the elastic steel plate is summed to obtain L 总 When the cutter head of the pipe jacking machine enters, ensure that the cutter head ring is larger than L 总 value, and then rotate the cutter head.

9. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1 is characterized in that: During the receiving excavation in step 4, during the pressure reduction test, it is necessary to ensure that there is no pressurization within 30 minutes after the chamber pressure drops to 0.

10. The method for launching and receiving slurry-balanced pipe jacking in water-rich loose strata according to claim 1, characterized in that: In the step 5, the sealing plate in the tunnel door sealing is a processed steel ring, which is welded and fixed to the circular steel ring at the tunnel door, and a diagonal brace is provided at the rear for reinforcement.

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