Pipe jacking construction method for large-section and small clear-distance double tunnels in parallel passing through complex strata

Abstract

The present invention provides a pipe jacking construction method for large-section and small-clearance double tunnels in parallel through complex strata. The first pipe jacking is jacked into the soft-upper and hard-lower complex strata, and the static crushing method is adopted. According to the hole position layout diagram on the ground surface, the rock-breaking agent is drilled and put in for rock-breaking jacking. At the same time, the second pipe jacking is jacked from the normal clay layer into the soft-upper and hard-lower complex strata; after the first pipe jacking passes through the soft-upper and hard-lower rock stratum, it continues to jack into the normal clay section. When the second pipe jacking passes through the soft-upper and hard-lower rock stratum, the rock-breaking agent is drilled and put in for rock-breaking jacking according to the hole position layout diagram on the ground surface; both the first pipe jacking and the second pipe jacking are jacked in the normal clay section until the receiving well; for the large-section and small-clearance parallel pipe jacking, the end step distance L of the parallel pipe jacking is determined through the relevant physical and mechanical parameters of the stratum and the ground surface settlement; the static blasting method is adopted for passing through the soft-upper and hard-lower complex strata, which is faster than the traditional method of using a pneumatic pick to break the rock mass in the open caisson.

Description

Technical Field

[0001] The present invention relates to the field of pipe jacking construction, and particularly to a pipe jacking construction method for two parallel large-section and small-clearance tunnels passing through complex strata. Background Art

[0002] With the development and utilization of underground space, pipe jacking projects, as a non-excavation technology, have also developed rapidly. In railway and highway tunnels, parallel pipe jacking projects have become very common. The settlement of the ground caused by parallel pipe jacking construction has always been the focus of attention, and many scholars have conducted in-depth research on it. The premise of current research, whether it is numerical simulation, model test or theoretical research, is that the prior pipe is constructed first and then the subsequent pipe is constructed, without considering the impact on ground settlement during the simultaneous construction of parallel pipe jacking; in view of requirements such as efficiency and construction period in actual projects, simultaneous jacking of parallel pipe jacking has become an inevitable problem.

[0003] During the pipe jacking construction process, more and more complex geological conditions such as soft upper and hard lower rock formations are encountered. According to the conventional construction technology, rock can be broken by pneumatic pick, or slurry balance mechanical jacking (equipped with imported special rock drilling tool pipe heads) can be used. Using manual pneumatic pick to break rock has a poor working environment and slow progress, and is only suitable for dealing with local rock obstacles and is not suitable for long-distance rock breaking into holes; using slurry balance mechanical jacking (equipped with imported special rock drilling tool pipe heads) is expensive and requires skill training, increasing project investment and being uneconomical. If it is changed to blasting and large-scale excavation construction, it will affect the lives of residents and pose a safety threat to nearby buildings and personnel. Currently, the research on pipe jacking mainly focuses on geologically uniform sections and curved sections, and there is less research on how to effectively construct in non-uniform strata, especially soft upper and hard lower strata.

[0004] Therefore, in view of the problems existing in the above technologies, a new pipe jacking construction method is urgently needed, which can not only overcome technical problems such as "complex strata, large section, small clearance, and two parallel tunnels", but also meet the requirements of safety, economy, environmental protection, applicability, and high work efficiency. Summary of the Invention

[0005] The main purpose of the present invention is to provide a pipe jacking construction method for two parallel large-section and small-clearance tunnels passing through complex strata, which solves the technical problems of parallel pipe jacking with large section and small clearance passing through complex strata such as compressible clay, soft upper and hard lower limestone, and mudstone.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a pipe jacking construction method for two parallel large-section and small-clearance tunnels passing through complex strata, the method comprising: S1. The prior pipe jacking is jacked into the soft upper and hard lower complex strata, and the static crushing method is adopted. The ground surface drills holes and injects rock-breaking agents for rock breaking and jacking according to the hole position layout diagram. At the same time, the subsequent pipe jacking is jacked from the normal clay layer into the soft upper and hard lower complex strata;

[0007] S2. After the leading pipe jacking passes through the upper-soft and lower-hard rock stratum, it continues to jack into the normal clay section. When the trailing pipe jacking passes through the upper-soft and lower-hard rock stratum, the ground surface drills holes according to the hole layout diagram and injects rock-breaking agents for rock jacking.

[0008] S3. Both the leading pipe jacking and the trailing pipe jacking are jacked into the receiving well in the normal clay section; for the large-section and small-spacing parallel pipe jacking, the step distance L between the ends of the parallel pipe jacking is determined through the relevant physical and mechanical parameters of the stratum and the ground settlement.

[0009] S4. When the leading pipe jacking and the trailing pipe jacking pass through the interval section of the upper-soft and lower-hard complex stratum, the stratum distribution on the heading face from the jacking direction is that the clay is getting less and the limestone is getting more. The interval section of the upper-soft and lower-hard complex stratum is mainly distributed with clay before and after, and the pipe jacking can be normally jacked.

[0010] In the preferred solution, the specific construction method is as follows:

[0011] A1. Calculate and determine through the physical and mechanical parameters of the stratum and the requirements of ground settlement that the optimal step distance between the ends of the leading pipe jacking and the trailing pipe jacking is not less than L. The clay layer before the leading pipe jacking enters the rock between the interface of the leading pipe jacking end and the hard rock stratum of the leading pipe jacking and the clay layer before the trailing pipe jacking enters the rock between the interface of the trailing pipe jacking end and the hard rock stratum of the trailing pipe jacking are normally jacked under the action of the pipe jacking machine until the interface of the hard rock stratum of the leading pipe jacking.

[0012] A2. When the leading pipe jacking is jacked in the upper-soft and lower-hard complex stratum section of the leading pipe jacking, and when the clay layer before the trailing pipe jacking enters the rock and the trailing pipe jacking is jacked in the upper-soft and lower-hard complex stratum section, always ensure that the distance between the ends of the leading pipe jacking and the trailing pipe jacking is not less than L. If necessary, the construction of the trailing pipe jacking can be suspended.

[0013] A3. Before the leading pipe jacking and the trailing pipe jacking are jacked in the upper-soft and lower-hard complex stratum section of the leading pipe jacking and the upper-soft and lower-hard complex stratum section of the trailing pipe jacking, use the drilling equipment of the screw air drill to drill holes on the ground surface in the complex interval section. There are two types of construction hole diameters: one is a small hole, which is an injection hole for the agent, and the other is a large hole, which is a free surface fragmentation hole;

[0014] The drilling depth reaches the bottom elevation of the pipe jacking;

[0015] Arrange 5 - 6 rows of small holes and 4 - 5 rows of large holes on the ground surface in the complex interval section. The hole spacing along the jacking direction is 50 - 60 cm, and the lateral spacing can be adjusted according to the actual construction conditions on site;

[0016] A4. After the drilling is completed, inject the rock-breaking agent into the small holes. After the chemical reaction of the rock-breaking agent occurs, the rock-breaking cracks in the small holes develop along the direction of the large holes;

[0017] After each pipe section is jacked, carry out the next stage of rock breaking and jacking operations, and cycle the construction until the upper-soft and lower-hard complex stratum section of the leading pipe jacking;

[0018] A5. The jacking principle and construction technology are the same as those of the clay layer after the first jacking pipe enters the rock and the soft upper and hard lower complex strata section after the jacking pipe enters the rock.

[0019] A5. When the leading and trailing jacking pipes are pushed into the clay layer after the leading jacking pipe enters the rock, or into the complex stratum section with soft top and hard bottom of the trailing jacking pipe, always ensure that the distance between the end of the leading jacking pipe and the end of the trailing jacking pipe is not less than L until the two jacking pipes are connected.

[0020] In the preferred solution, the first jacking pipe and the second jacking pipe are normally pushed into the clay:

[0021] The optimal step distance L between the leading and trailing jacking pipe ends is determined by the physical and mechanical parameters of the formation and the surface settlement requirements. In the clay layer, the two jacking pipes are pushed forward normally by the jacking machine until the leading jacking pipe reaches the complex formation with soft top and hard bottom.

[0022] In the preferred embodiment, the length of L is 5 times the length of the pipe segment.

[0023] In the preferred embodiment, the drilling method in step A3 is: the drill rod of the drilling equipment is first vertically drilled to the bottom elevation of the top pipe, and after the drill rod is pulled out, the angle of the drill rod is adjusted to drill again, and cross drilling is performed;

[0024] The cross section of the small hole is made into two opposing fan-shaped structures.

[0025] The present invention provides a method for jacking pipes in parallel with large-section and small-clearance double-holes through complex strata. The method is economical: compared with improving the tool, the static blasting method is used to break the rock and jack in the upper soft and lower hard rock strata, and no additional project investment and cutterhead operation skill training are required, so the cost is low. High work efficiency: when the double-hole ends are jacked synchronously with the optimal step distance not less than L, the process of jacking pipes after jacking is wide and efficient compared with the completion of the jacking of the first jacking pipe; the static blasting method is used to break the rock mass faster than the traditional pneumatic pick for opening the cabin when crossing the complex strata with soft upper and hard lower strata. Feasibility: The surface settlement of the large-section and small-clearance double-hole parallel jacking pipes can be controlled within a reasonable settlement range during the jacking process of the full-section clay layer and the complex strata with soft upper and hard upper strata; large-hole free-face crushing holes and small-hole injection holes are drilled on the corresponding surface in the upper soft and lower hard rock strata, and the cracks generated by the chemical reaction of the crushing agent in the injection hole extend to the large hole, which has a good rock breaking effect. Safety: The rock breaking and jacking method that combines large-hole free surface crushing and small-hole injection holes for soft upper and hard rock layers has a lower safety factor than the traditional rock breaking and jacking with a pneumatic pick and blasting excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] Figure 1 It is a schematic longitudinal section diagram of the pipe jacking of the present invention passing through the upper soft and lower hard rock stratum;

[0028] Figure 2 It is a plan layout diagram of the surface hole positions of the pipe jacking of the present invention passing through the upper soft and lower hard rock stratum;

[0029] Figure 3 It is a schematic cross-sectional diagram of the drilling of the drilling equipment of the present invention.

[0030] In the figure: the front pipe jacking end 1; the rear pipe jacking end 2; the interface of the front pipe jacking with the hard rock stratum 3; the interface of the rear pipe jacking with the hard rock stratum 4; the clay layer before the front pipe jacking enters the rock 5; the clay layer before the rear pipe jacking enters the rock 6; the upper soft and lower hard complex stratum section of the front pipe jacking 7; the surface of the complex interval section 8; the small hole 9; the large hole 10; the clay layer after the front pipe jacking enters the rock 11; the upper soft and lower hard complex stratum section of the rear pipe jacking 12; the clay layer after the rear pipe jacking enters the rock 13; the drill pipe 14; the drilling equipment 15. Specific implementation manners

[0031] Example 1

[0032] As Figures 1 to 3 shown, a pipe jacking construction method for a large-section and small clear distance double-tunnel parallel arrangement passing through a complex stratum, the method includes: the front pipe jacking is jacked to the upper soft and lower hard complex stratum, and the static crushing method is adopted. According to the hole position layout diagram on the ground surface, holes are drilled to put the rock-breaking agent for rock breaking and jacking, and at the same time, the rear pipe jacking is jacked from the normal clay layer to the upper soft and lower hard complex stratum;

[0033] After the front pipe jacking passes through the upper soft and lower hard rock stratum, it continues to be jacked into the normal clay section. When the rear pipe jacking passes through the upper soft and lower hard rock stratum, according to the hole position layout diagram on the ground surface, holes are drilled to put the rock-breaking agent for rock breaking and jacking;

[0034] Both the front pipe jacking and the rear pipe jacking are jacked in the normal clay section until the receiving well; for the large-section and small clear distance parallel pipe jacking, the step distance L of the parallel pipe jacking ends is determined through the relevant physical and mechanical parameters of the stratum and the surface settlement;

[0035] When the front pipe jacking and the rear pipe jacking pass through the upper soft and lower hard complex stratum interval section, the stratum distribution on the heading face from the jacking direction is that the clay is less and less, and the limestone is more and more. The front and rear of the upper soft and lower hard complex stratum interval section are mainly distributed with clay, and the pipe jacking can be normally jacked.

[0036] Both pipe jackings are jacked in the clay layer at the same time, and the optimal step distance of the pipe jacking ends is determined through numerical simulation calculation and relevant surface monitoring data.

[0037] The static crushing method is adopted. By drilling injection holes and free surface crushing holes on the ground surface in the upper soft and lower hard stratum section, the rock-breaking agent is put into the injection holes for rock breaking, and the cracks develop towards the free crushing holes.

[0038] Example 2

[0039] As Figures 1 to 3 shown, in combination with the embodiments, it is further illustrated that the optimal step distance between the leading pipe jacking end 1 and the trailing pipe jacking end 2 is calculated and determined to be not less than L based on the formation physical and mechanical parameters and the surface settlement requirements. The clay layer 5 before the leading pipe jacking enters the rock layer between the leading pipe jacking end 1 and the interface 3 of the leading pipe jacking hard rock layer, and the clay layer 6 before the trailing pipe jacking enters the rock layer between the trailing pipe jacking end 2 and the interface 4 of the trailing pipe jacking hard rock layer. The two pipe jackings are normally jacked under the action of the pipe jacking machine until the interface 3 of the leading pipe jacking hard rock layer.

[0040] When the leading pipe jacking is jacked in the soft upper and hard lower complex formation section 7 of the leading pipe jacking, and when the clay layer 6 before the trailing pipe jacking enters the rock layer and the soft upper and hard lower complex formation section 12 of the trailing pipe jacking are jacked, it is always ensured that the distance between the leading pipe jacking end 1 and the trailing pipe jacking end 2 is not less than L. If necessary, the construction of the trailing pipe jacking can be suspended.

[0041] Before the leading pipe jacking and the trailing pipe jacking are jacked in the soft upper and hard lower complex formation section 7 of the leading pipe jacking and the soft upper and hard lower complex formation section 12 of the trailing pipe jacking, drilling is carried out on the surface 8 of the complex section by using the drilling equipment 15 of the screw air drill. There are two types of construction hole diameters: one is the small hole 9, and the small hole 9 is the medicine injection hole, and the other is the large hole 10, and the large hole 10 is the free surface fragmentation hole.

[0042] The drilling depth reaches the bottom elevation of the pipe jacking.

[0043] 5 - 6 rows of small holes 9 and 4 - 5 rows of large holes 10 are arranged on the surface 8 of the complex section. The hole position spacing along the jacking direction is 50 - 60 cm, and the lateral spacing can be adjusted according to the actual construction conditions on site.

[0044] After the drilling is completed, the fragmentation agent is put into the 75 - mm small hole 9. The charging depth is 4 m, and the single - hole explosive amount is about 0.018 m 3 , then about 29 kg of fragmentation agent for a single hole, including 7.25 kg of water and 21.75 kg of expansion agent. The 200 - mm large hole free surface fragmentation large hole 10 remains unchanged.

[0045] One is the 75 - mm small hole medicine injection hole, and the other is the 200 - mm large hole free surface fragmentation hole. The drilling depth reaches the bottom elevation of the pipe jacking, and the maximum depth is 19 m. On the surface 8 of the 38 m×3.6 m complex section, 5 rows of 75 - mm small holes 9 and 4 rows of 200 - mm large holes 10 are arranged. The hole position spacing along the jacking direction is 50 cm, and the lateral spacing can be adjusted according to the actual construction conditions on site.

[0046] After the drilling is completed, the fragmentation agent is put into the small hole 9. After the fragmentation agent undergoes a chemical reaction, the rock - breaking cracks of the small hole 9 develop along the direction of the large hole 10.

[0047] After each pipe section is pushed in, the next stage of rock breaking and pushing operation is carried out, and the construction is cyclically carried out until the complex formation section 7 with soft upper and hard lower parts is pushed in.

[0048] The clay layer 11 after the first jacking pipe enters the rock is jacked, and the complex formation section 12 with soft upper and hard lower parts of the subsequent jacking pipe is jacked. The jacking principle and construction technology are the same as those of the complex formation section 7 with soft upper and hard lower parts of the first jacking pipe and the clay layer 6 before the subsequent jacking pipe enters the rock.

[0049] When the leading and trailing jacking pipes are pushed into the clay layer 11 after the leading jacking pipe enters the rock and the complex stratum section 12 with soft upper and hard lower parts of the trailing jacking pipe, always ensure that the distance between the leading jacking pipe end 1 and the trailing jacking pipe end 2 is not less than L until the two jacking pipes are connected.

[0050] In the preferred solution, the first jacking pipe and the second jacking pipe are normally pushed into the clay:

[0051] The optimal step distance L of the leading jacking pipe end 1 and the trailing jacking pipe end 2 is determined by the physical and mechanical parameters of the formation and the surface settlement requirements. In the clay layer, the two jacking pipes are pushed forward normally under the action of the jacking machine until the leading jacking pipe reaches the complex formation with soft upper part and hard lower part.

[0052] In the preferred embodiment, the length of L is 5 times the length of the pipe segment.

[0053] In the preferred embodiment, the drilling method in step A3 is as follows: the drill rod 14 of the drilling equipment 15 is first vertically drilled to the bottom elevation of the top pipe, and after the drill rod 14 is pulled out, the angle of the drill rod 14 is adjusted to drill again, thereby performing cross drilling.

[0054] The cross section of the small hole 9 is made into two opposite fan-shaped structures. Figure 3 In the structure shown in the figure, when the crushing agent is placed in the small hole 9, the charge depth is 4m, and the amount of explosives in a single hole is about 0.018m 3 These drugs are transported to the bottom of the small hole 9 through the fan-shaped funnel structure. The expansion inside the small hole 9 will be more fan-shaped, and the cracks will develop towards the free crushing hole. The crushing effect is good, but the construction speed is slow. It is suitable for use in more complex terrains, such as large pieces of hard granite. This method can better achieve crushing.

[0055] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A pipe jacking construction method for large-section and small clear distance double tunnels running in parallel through complex strata, characterized in that: The method includes: S1. The leading pipe jacking is jacked into the soft upper and hard lower complex stratum. The static crushing method is adopted. According to the hole position layout diagram on the ground surface, the rock-breaking agent is drilled and put into the hole for rock breaking and jacking. At the same time, the trailing pipe jacking is jacked from the normal clay stratum into the soft upper and hard lower complex stratum; S2. After the leading pipe jacking penetrates the soft upper and hard lower rock stratum, it continues to be jacked into the normal clay section. When the trailing pipe jacking penetrates the soft upper and hard lower rock stratum, according to the hole position layout diagram on the ground surface, the rock-breaking agent is drilled and put into the hole for rock breaking and jacking; S3. Both the leading pipe jacking and the trailing pipe jacking are jacked in the normal clay section until the receiving well. For the large-section and small-spacing parallel pipe jacking, the end step distance L of the parallel pipe jacking is determined by the relevant physical and mechanical parameters of the stratum and the ground surface settlement; S4. In the interval section of the soft upper and hard lower complex stratum where the leading pipe jacking and the trailing pipe jacking pass through, from the tunnel face in the jacking direction, the clay in the stratum distribution is less and less, and the limestone is more and more. The interval section of the soft upper and hard lower complex stratum is mainly distributed with clay before and after, and the pipe jacking can be normally jacked; 2. The pipe jacking construction method for large-section and small clear distance double tunnels running in parallel through complex strata according to claim 1, characterized in that: The specific construction method is as follows: A1. Calculate and determine that the optimal step distance between the leading pipe jacking end (1) and the trailing pipe jacking end (2) is not less than L through the physical and mechanical parameters of the stratum and the requirements of the ground surface settlement. The clay stratum (5) before the leading pipe jacking enters the rock between the leading pipe jacking end (1) and the interface (3) of the hard rock stratum of the leading pipe jacking and the clay stratum (6) before the trailing pipe jacking enters the rock between the trailing pipe jacking end (2) and the interface (4) of the hard rock stratum of the trailing pipe jacking. The two pipe jackings are normally jacked under the action of the pipe jacking machine until the interface (3) of the hard rock stratum of the leading pipe jacking; A2. When the leading pipe jacking is jacked in the soft upper and hard lower complex stratum section (7) of the leading pipe jacking, and when the trailing pipe jacking is jacked in the clay stratum (6) before the trailing pipe jacking enters the rock and the soft upper and hard lower complex stratum section (12) of the trailing pipe jacking, always ensure that the distance between the leading pipe jacking end (1) and the trailing pipe jacking end (2) is not less than L. If necessary, the construction of the trailing pipe jacking can be suspended; A3. Before the leading pipe jacking and the trailing pipe jacking are jacked in the soft upper and hard lower complex stratum section (7) of the leading pipe jacking and the soft upper and hard lower complex stratum section (12) of the trailing pipe jacking, use the drilling equipment (15) of the screw air drill to drill holes on the ground surface (8) of the complex interval section. There are two types of construction hole diameters: one is the small hole (9), and the small hole (9) is the hole for injecting the agent; the other is the large hole (10), and the large hole (10) is the free surface rock-breaking hole; The drilling depth reaches the bottom elevation of the pipe jacking; Arrange 5-6 rows of small holes (9) and 4-5 rows of large holes (10) on the ground surface (8) of the complex interval section. The hole position spacing along the jacking direction is 50-60 cm, and the lateral spacing can be adjusted according to the actual construction conditions on site; A4. After the drilling is completed, put the rock-breaking agent into the small hole (9). After the rock-breaking agent undergoes a chemical reaction, the rock-breaking cracks in the small hole (9) develop along the direction of the large hole (10); After each pipe joint is jacked, carry out the next stage of rock breaking and jacking operations, and cycle the construction until the soft upper and hard lower complex stratum section (7) of the leading pipe jacking; A5. When the leading pipe jacking is jacked in the clay stratum (11) after entering the rock and the trailing pipe jacking is jacked in the soft upper and hard lower complex stratum section (12), the jacking principle and construction technology are the same as those of the soft upper and hard lower complex stratum section (7) of the leading pipe jacking and the clay stratum (6) before the trailing pipe jacking enters the rock; A5. When the leading jacking pipe and the trailing jacking pipe are pushed into the clay layer (11) after the leading jacking pipe enters the rock and the complex stratum section (12) with soft upper part and hard lower part of the trailing jacking pipe, always ensure that the distance between the end of the leading jacking pipe (1) and the end of the trailing jacking pipe (2) is not less than L until the two jacking pipes are connected.

3. The pipe jacking construction method for large-section small clear distance double tunnels in parallel through complex strata according to claim 2, characterized in that: Normal jacking of the leading and trailing pipes in clay: The optimal step distance L of the leading jacking pipe end (1) and the trailing jacking pipe end (2) is determined by the physical and mechanical parameters of the formation and the surface settlement requirements. The two jacking pipes are normally advanced in the clay layer under the action of the jacking machine until the leading jacking pipe reaches the complex formation with soft top and hard bottom.

4. The pipe jacking construction method for a large-section and small clear distance double-tunnel parallel arrangement passing through complex strata according to claim 3, characterized in that: The length of L is: 5 times the length of the pipe segment.

5. The pipe jacking construction method for large-section and small clear distance double tunnels running in parallel through complex strata according to claim 2, characterized in that: The drilling method in step A3 is as follows: the drill rod (14) of the drilling equipment (15) is first vertically drilled to the bottom elevation of the top pipe, and after the drill rod (14) is pulled out, the angle of the drill rod (14) is adjusted to drill again, thereby performing cross drilling; The cross section of the small hole (9) is formed into two opposing fan-shaped structures.

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