Loess tunnel base reinforced composite multifunctional pile foundation and construction method

Abstract

The invention discloses a loess tunnel base reinforcement composite multifunctional pile foundation and a construction method, and relates to the technical field of tunnel base reinforcement. Comprising a foundation, a tunnel main body is arranged on the upper side of the foundation, steel pipe piles are uniformly arranged in a bottom foundation corresponding to the lower surface of the tunnel main body, and cement soil compaction piles are arranged in the foundation between the steel pipe piles; the steel pipe pile comprises a steel pipe body, a reinforcing ring, a rectangular notch, a first limiting block, a conical head, a second limiting block, a conical sleeve, a through hole and a fastener. The cement soil compaction pile comprises a semicircular plate, a conical barb and a filling body. According to the construction method, the steel pipe piles are constructed and then the cement soil compaction piles are constructed, so that the safe bearing of the foundation reinforcement and tunnel body protection structure is ensured, and the cement soil compaction piles are ensured not to be broken during the construction period and the operation stage so as to avoid collapsing and settling, thereby ensuring the safety and reliability of the whole service life of the tunnel structure; the steel pipe piles and the cement soil compaction piles are convenient to install and not prone to damage.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel base reinforcement, and in particular to a loess tunnel base reinforcement composite multifunctional pile foundation and a construction method. Background Art

[0002] Cement-soil compaction piles are mainly used to eliminate the collapsibility of the base loess and improve the bearing capacity of the foundation in the construction of loess tunnels. However, since the base surrounding rock of loess tunnels is usually relatively weak, the tunnel body deforms and becomes unstable, and the invert arch rises and cracks due to unloading and redistribution of ground stress after construction and excavation. The cement-soil compaction piles generate large tensile stress due to the upward deformation of the base surrounding rock, which causes the pile body to break and lose its function of eliminating collapsibility and reinforcing the surrounding rock. This leads to deformation, instability and damage of the tunnel structure during the construction phase, and bulging of the tunnel invert arch due to groundwater intrusion in the later stage, resulting in mud and slurry. This seriously affects traffic safety operations.

[0003] 1. In the prior art, loess, as a special type of soil, will encounter many challenges during tunnel construction. Loess has the characteristics of high porosity, easy to be eroded by water, and significant collapsibility, which makes the base reinforcement work particularly complex and important when building tunnels in loess areas. At present, the commonly used base reinforcements are mainly cement soil compaction piles and rotary jet piles. However, due to the weak surrounding rock of the loess tunnel base, the bottom surrounding rock uplifts and deforms greatly after construction and excavation, and the pile foundation is subjected to large tensile stress. The materials used for cement soil compaction piles and rotary jet piles are cement mortar materials with low tensile strength. Therefore, the pile foundation is very easy to break. The pile foundation loses its design function in the early stage of construction, resulting in cracking and damage of the tunnel structure and the arch structure in the later stage of construction and later operation, and the safety and reliability of the structure cannot be guaranteed; 2. In the prior art, steel pipe piles have low strength during use and are not easy to insert into the foundation. It is time-consuming and laborious to connect the upper and lower adjacent steel pipe piles. At the same time, the cement soil compaction piles are not tightly combined with the foundation and are easily deformed and damaged. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a loess tunnel base reinforcement composite multifunctional pile foundation and a construction method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a loess tunnel base reinforcement composite multifunctional pile foundation, comprising a foundation, a tunnel body is arranged on the upper side of the foundation, steel pipe piles are evenly arranged in the bottom foundation corresponding to the lower surface of the tunnel body, and cement soil compaction piles are arranged in the foundation between the steel pipe piles; The steel pipe pile comprises a steel pipe body, a reinforcement ring, a rectangular notch, a first limit block, a conical head, a second limit block, a conical sleeve, a through hole and a fastener, two reinforcement rings are fixedly installed at the lower edge of the inner wall of the steel pipe body, and rectangular notches are opened on the left and right sides of the reinforcement ring close to the outside, a conical head is installed on the lower surface of the steel pipe body corresponding to the rectangular notch through the first limit block, a second limit block is fixedly installed at the upper position of the inner wall of the steel pipe body, and conical sleeves are uniformly sleeved on the outer surface of the steel pipe body from top to bottom, through holes are symmetrically opened on the conical sleeve and the side wall of the steel pipe body, and fastening components are installed with threads in the through holes; The cement soil compaction pile comprises a semicircular plate, a conical barb and a filling body. Two semicircular plates are arranged on the left and right, and the conical barbs are evenly arranged on the inner and outer side walls of the semicircular plates. The filling body is filled between the semicircular plates.

[0006] As a preferred technical solution of the present invention, the steel pipe body has a diameter of 108 mm, a wall thickness of 6 mm, a pile length of 6 m-10 m, and is arranged in a plum blossom shape with a spacing of 1 m-1.2 m.

[0007] As a preferred technical solution of the present invention, the steel pipe piles are arranged one on each side at the junction of the tunnel body side wall corner inverted arch, with an angle of 10-20° with the vertical, and 6-10 piles are arranged vertically at the inverted arch according to the span of the tunnel body.

[0008] As a preferred technical solution of the present invention, the steel pipe body is made of steel of no less than HRB400, and holes are punched within the range of 1m-1.5m at the bottom end of the steel pipe body, with a hole diameter of 2m-5mm, a longitudinal hole spacing of 10m-15cm, and 2-3 holes evenly distributed in the annular direction.

[0009] As a preferred technical solution of the present invention, the steel pipe body and the corresponding upper and lower through holes and fasteners on the conical sleeve are arranged in a cross shape.

[0010] As a preferred technical solution of the present invention, the cement soil compaction piles have a diameter of 0.4m-0.6m, a pile length of 10m-15m, a plum blossom-shaped arrangement, and a spacing of 1m-1.2m.

[0011] As a preferred technical solution of the present invention, the semicircular plate is a stainless steel mesh plate, and the thickness of the semicircular plate is 3mm-5mm.

[0012] As a preferred technical solution of the present invention, the filling body adopts early-strength silicate cement with a strength grade not lower than P.O42.5R, and the soil adopts silty clay with a maximum particle size less than 0.076 mm.

[0013] A loess tunnel base reinforcement composite multifunctional pile foundation construction method comprises the following steps: S1. Steel pipe pile placement: Move the diesel hammer pile driver into the tunnel body, and arrange the steel pipe piles at the junction of the side wall corner and the inverted arch of the tunnel body, with one pile on each side, and an angle of 10-20° with the vertical. At the inverted arch, 6-10 piles are arranged vertically according to the span of the tunnel body; S2, steel pipe pile installation: lift the steel pipe pile and insert it into the foundation, sink the steel pipe pile by a diesel hammer pile driver, insert the second limit block on the upper side of the lower steel pipe body through the rectangular notch into the reinforcing rings in the upper adjacent steel pipe body, and sink the steel pipe pile to the designed depth; S3. Grouting of steel pipe piles: Cut the steel pipe piles and perform pressure grouting. One day after the steel pipe piles are completed, the base cement soil compaction piles are constructed; S4. Cement soil compaction pile drilling: Drill holes between steel pipe piles using a diesel hammer pile driver to the designed depth; S5. Installation of soil compaction piles: symmetrically place the left-right symmetrical semicircular plates into the hole, then pressurize the filling body into the space between the left and right semicircular plates, and squeeze the semicircular plates to the inner wall of the hole on both sides.

[0014] Beneficial Effects Compared with the prior art, the present invention provides a loess tunnel base reinforcement composite multifunctional pile foundation and construction method, which has the following beneficial effects: 1. The loess tunnel base reinforcement composite multifunctional pile foundation and construction method, by setting and applying steel pipe piles and then applying cement soil compaction piles, not only ensures the safe bearing capacity of the base reinforcement to protect the tunnel structure, but also ensures that the cement soil compaction piles will not break during the construction and operation stages, thereby avoiding wet collapse and settlement, thereby ensuring the safety and reliability of the tunnel structure throughout its life cycle.

[0015] 2. The loess tunnel base reinforcement composite multifunctional pile foundation and construction method greatly improves the strength of the steel pipe pile by setting a conical head, a conical sleeve and fasteners in the steel pipe pile, and facilitates the docking of the steel pipe pile, so that the cement soil compaction pile has high strength, can be tightly structured with the foundation, is easy to install and is not easy to damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a composite multifunctional pile foundation structure for reinforcing a loess tunnel base proposed by the present invention; Figure 2 A schematic diagram of a steel pipe pile structure for a loess tunnel base reinforcement composite multifunctional pile foundation proposed by the present invention; Figure 3 A cross-sectional view of a steel pipe pile for reinforcing a loess tunnel base composite multifunctional pile foundation proposed by the present invention; Figure 4A cross-sectional view of a cement-soil compaction pile for reinforcing a loess tunnel base composite multifunctional pile foundation proposed by the present invention; Figure 5 The present invention provides a schematic diagram of a composite multifunctional pile foundation for reinforcing a loess tunnel base and a construction method thereof.

[0017] In the figure: 1. foundation; 2. tunnel body; 3. steel pipe pile; 301. steel pipe body; 302. reinforcement ring; 303. rectangular notch; 304. first limit block; 305. conical head; 306. second limit block; 307. conical sleeve; 308. through hole; 309. fastener; 4. cement soil compaction pile; 401. semicircular plate; 402. conical barb; 403. filling body. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Please refer to Figure 1-Figure 5 The present invention discloses a loess tunnel base reinforcement composite multifunctional pile foundation, comprising a foundation 1, a tunnel body 2 is arranged on the upper side of the foundation 1, steel pipe piles 3 are evenly arranged in the bottom foundation 1 corresponding to the lower surface of the tunnel body 2, and cement soil compaction piles 4 are arranged in the foundation 1 between the steel pipe piles 3; The steel pipe pile 3 includes a steel pipe body 301, a reinforcement ring 302, a rectangular notch 303, a first limit block 304, a conical head 305, a second limit block 306, a conical sleeve 307, a through hole 308 and a fastener 309. Two reinforcement rings 302 are fixedly installed at the lower edge of the inner wall of the steel pipe body 301, and rectangular notches 303 are opened on the left and right sides of the reinforcement ring 302 close to the outside. The conical head 305 is installed on the lower surface of the steel pipe body 301 corresponding to the rectangular notch 303 through the first limit block 304, and the second limit block 306 is fixedly installed on the upper side of the inner wall of the steel pipe body 301. Conical sleeves 307 are uniformly sleeved on the outer surface of the steel pipe body 301 from top to bottom. Through holes 308 are symmetrically opened on the conical sleeve 307 and the side wall of the steel pipe body 301, and fastening components are installed in the inner thread of the through hole 308; The cement soil compaction pile 4 includes a semicircular plate 401 , a conical barb 402 and a filling body 403 . Two semicircular plates 401 are arranged on the left and right, and the conical barbs 402 are evenly arranged on the inner and outer side walls of the semicircular plates 401 . The filling body 403 is filled between the semicircular plates 401 .

[0020] Specifically, the steel pipe body 301 has a diameter of 108 mm, a wall thickness of 6 mm, a pile length of 6 m-10 m, and is arranged in a plum blossom shape with a spacing of 1 m-1.2 m.

[0021] In this embodiment, the steel pipe body 301 has good strength and is evenly arranged, resulting in a good reinforcement effect.

[0022] Specifically, the steel pipe piles 3 are arranged one on each side at the junction of the side wall corner and the inverted arch of the tunnel body 2, with an angle of 10-20° with the vertical, and 6-10 are vertically arranged at the inverted arch according to the span of the tunnel body 2.

[0023] In this embodiment, the steel pipe piles 3 are evenly arranged to improve the strength of the inverted arch portion of the tunnel body 2.

[0024] Specifically, the steel pipe body 301 is made of steel material not lower than HRB400, and holes are punched within the range of 1m-1.5m at the bottom end of the steel pipe body 301, with a hole diameter of 2m-5mm, a longitudinal hole spacing of 10m-15cm, and 2-3 holes are evenly distributed in the annular direction.

[0025] In this embodiment, the steel pipe body 301 has high strength, and drilling is convenient for subsequent pressure grouting.

[0026] Specifically, the steel pipe body 301 and the corresponding through holes 308 and fasteners 309 on the conical sleeve 307 are arranged in a cross shape.

[0027] In this embodiment, the tapered sleeve 307 and the fastener 309 make the steel pipe body 301 stronger, and the tapered sleeve 307 facilitates the insertion of the steel pipe body 301 into the foundation 1 .

[0028] Specifically, the cement soil compaction piles 4 have a diameter of 0.4m-0.6m, a pile length of 10m-15m, a plum blossom arrangement, and a spacing of 1m-1.2m.

[0029] In this embodiment, the cement soil compaction piles 4 are evenly distributed, which has a better reinforcement effect on the foundation 1 .

[0030] Specifically, the semicircular plate 401 is made of a stainless steel mesh plate, and the thickness of the semicircular plate 401 is 3 mm-5 mm.

[0031] In this embodiment, the semicircular plate 401 facilitates the outflow of the filling body 403, and the bonding effect is better.

[0032] Specifically, the filler 403 is made of early-strength silicate cement with a strength grade not less than P.O42.5R, and the soil is silty clay with a maximum particle size less than 0.076 mm.

[0033] In this embodiment, the filler 403 has high strength, the ratio of cement to soil in the filler 403 is 0.3:1, and the water content of the cement soil is 20-30%.

[0034] A loess tunnel base reinforcement composite multifunctional pile foundation construction method comprises the following steps: S1, steel pipe pile placement: move the diesel hammer pile driver into the tunnel body 2, arrange the steel pipe piles 3 at the junction of the side wall corner and the inverted arch of the tunnel body 2, one on each side, with an angle of 10-20° with the vertical, and arrange 6-10 piles vertically at the inverted arch according to the span of the tunnel body 2; S2, installation of steel pipe piles: lift the steel pipe pile 3 and insert it into the foundation 1, sink the steel pipe pile 3 by a diesel hammer pile driver, insert the second limit block 306 on the upper side of the lower steel pipe body 301 through the rectangular notch 303 and between the reinforcing rings 302 in the upper adjacent steel pipe body 301, and sink the steel pipe pile 3 to the designed depth; S3, steel pipe pile grouting: cutting the steel pipe pile 3 and performing pressure grouting. One day after the steel pipe pile 3 is completed, the base cement soil compaction pile 4 is constructed; S4, cement soil compaction pile drilling: drilling between the steel pipe piles 3 by a diesel hammer pile driver to a designed depth; S5. Installation of soil compaction piles: symmetrically place the left-right symmetrical semicircular plates 401 into the hole, and then inject the filler 403 between the left and right semicircular plates 401 under pressure, and squeeze the semicircular plates 401 to both sides to squeeze the inner wall of the hole.

[0035] The working principle and use process of the present invention are as follows: when in use, after the side wall of the tunnel body 2 is constructed and the inverted arch soil is excavated, the steel pipe piles are constructed, and the diesel hammer pile driver is moved into the tunnel body 2. The steel pipe piles 3 are arranged at the junction of the side wall corner of the tunnel body 2 and the inverted arch, with one on each side, and the vertical angle is 10-20 degrees. At the inverted arch, 6-10 steel pipe piles are arranged vertically according to the span of the tunnel body 2. The steel pipe piles 3 are hoisted and inserted into the foundation 1. The steel pipe piles 3 are sunk by the diesel hammer pile driver, so that the lower steel pipe body 301 The second upper limit block 306 is inserted through the rectangular notch 303 between the reinforcing rings 302 in the upper adjacent steel pipe body 301, and the steel pipe pile 3 is sunk to the designed depth. The steel pipe pile 3 is cut and pressure grouting is performed. One day after the steel pipe pile 3 is completed, the base cement soil compaction pile 4 is constructed. A diesel hammer pile driver is used to make holes between the steel pipe piles 3 to the designed depth, and the left and right symmetrical semicircular plates 401 are symmetrically placed in the holes, and then the filling body 403 is pressure-injected between the left and right semicircular plates 401 to make the semicircular The plate 401 squeezes the inner wall of the hole to both sides. By setting and installing the steel pipe pile 3 and then installing the cement soil compaction pile 4, not only the safe bearing of the foundation 1 to reinforce and protect the tunnel structure is guaranteed, but also the cement soil compaction pile 4 can be guaranteed not to break during the construction period and the operation stage, thereby avoiding the collapse and settlement, thereby ensuring the safety and reliability of the tunnel body 2 structure throughout its life. The first limit block 304 in the steel pipe pile 3 is inserted between the upper and lower reinforcement rings 302 through the rectangular notch 303, and the first limit block 304 is rotated to achieve the installation of the conical head 305. On the lower surface of the steel pipe body 301, it is convenient for the steel pipe pile 3 to be inserted into the foundation 1. The upper second limit block 306 is convenient for docking with the upper steel pipe pile 3. The strength of the steel pipe pile 3 is greatly improved through the reinforcing ring 302, the conical sleeve 307 and the fastener 309, making it not easy to be damaged. The filling body 403 is inserted between the left and right semicircular plates 401, and the conical barbs 402 between the inner and outer walls of the semicircular plates 401 are inserted into the foundation 1 and the filling body 403, so that the cement soil compaction pile 4 has high strength, can be tightly structured with the foundation 1, is convenient for installation, and is not easy to be damaged.

[0036] In summary, the loess tunnel base reinforcement composite multifunctional pile foundation and construction method, by constructing steel pipe piles 3 and then cement soil compaction piles 4, not only ensures the safe bearing capacity of the foundation 1 to reinforce and protect the tunnel structure, but also ensures that the cement soil compaction piles 4 will not break during the construction and operation stages, thereby avoiding collapse and settlement, thereby ensuring the safety and reliability of the tunnel body 2 structure throughout its life cycle, and the steel pipe piles 3 and cement soil compaction piles 4 are strong, easy to install, and not easy to damage.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite multifunctional pile foundation for reinforcing a loess tunnel base, comprising a foundation (1), characterized in that: A tunnel body (2) is arranged on the upper side of the foundation (1), steel pipe piles (3) are evenly arranged in the bottom foundation (1) corresponding to the lower surface of the tunnel body (2), and cement soil compaction piles (4) are arranged in the foundation (1) between the steel pipe piles (3); The steel pipe pile (3) comprises a steel pipe body (301), a reinforcement ring (302), a rectangular notch (303), a first stopper (304), a conical head (305), a second stopper (306), a conical sleeve (307), a through hole (308) and a fastener (309). Two reinforcement rings (302) are fixedly mounted on the lower edge of the inner wall of the steel pipe body (301), and the reinforcement ring (302) close to the outside is provided with rectangular notches (303) on the left and right sides. (303) A conical head (305) is installed on the lower surface of the corresponding steel pipe body (301) through a first limit block (304), a second limit block (306) is fixedly installed on the upper side of the inner wall of the steel pipe body (301), and conical sleeves (307) are evenly sleeved on the outer surface of the steel pipe body (301) from top to bottom, and through holes (308) are symmetrically opened on the side wall of the conical sleeve (307) and the steel pipe body (301), and a fastening component is installed on the internal thread of the through hole (308); The cement soil compaction pile (4) comprises a semicircular plate (401), a conical barb (402) and a filling body (403), wherein two semicircular plates (401) are arranged on the left and right, and the conical barbs (402) are evenly arranged on the inner and outer side walls of the semicircular plates (401), and the filling body (403) is filled between the semicircular plates (401).

2. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The steel pipe body (301) has a diameter of 108 mm, a wall thickness of 6 mm, a pile length of 6 m-10 m, and is arranged in a plum blossom shape with a spacing of 1 m-1.2 m.

3. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The steel pipe piles (3) are arranged one on each side of the junction of the side wall corner and the inverted arch of the tunnel body (2), with an angle of 10-20° with the vertical, and 6-10 are arranged vertically at the inverted arch according to the span of the tunnel body (2).

4. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The steel pipe body (301) is made of steel material not lower than HRB400. The bottom end of the steel pipe body (301) is perforated within a range of 1m-1.5m, with a hole diameter of 2m-5mm, a longitudinal hole spacing of 10m-15cm, and 2-3 holes evenly distributed in the annular direction.

5. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The steel pipe body (301) and the conical sleeve (307) have corresponding through holes (308) and fasteners (309) arranged in a cross shape.

6. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The cement soil compaction piles (4) have a diameter of 0.4m-0.6m, a pile length of 10m-15m, and are arranged in a plum blossom shape with a spacing of 1m-1.2m.

7. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The semicircular plate (401) is a stainless steel mesh plate, and the thickness of the semicircular plate (401) is 3 mm to 5 mm.

8. The loess tunnel base reinforcement composite multifunctional pile foundation according to claim 1, characterized in that: The filling body (403) is made of early-strength silicate cement with a strength grade not less than P.O42.5R, and the soil is silty clay with a maximum particle size less than 0.076 mm.

9. A method for constructing a composite multifunctional pile foundation for reinforcing a loess tunnel base, the method being based on the composite multifunctional pile foundation for reinforcing a loess tunnel base as claimed in claim 1, characterized in that: The following steps are involved: S1. Steel pipe pile placement: Move the diesel hammer pile driver into the tunnel body (2), and arrange the steel pipe piles (3) at the junction of the side wall corner and the inverted arch of the tunnel body (2), with one pile arranged on each side, with an angle of 10-20° with the vertical, and 6-10 piles arranged vertically at the inverted arch according to the span of the tunnel body (2); S2, installation of steel pipe piles: hoisting the steel pipe pile (3) and inserting it into the foundation (1), sinking the steel pipe pile (3) by means of a diesel hammer pile driver, so that the second limit block (306) on the upper side of the lower steel pipe body (301) is inserted through the rectangular notch (303) between the reinforcing rings (302) in the upper adjacent steel pipe body (301), and sinking the steel pipe pile (3) to the designed depth; S3, steel pipe pile grouting: cutting the steel pipe pile (3) and performing pressure grouting. One day after the steel pipe pile (3) is completed, the base cement soil compaction pile (4) is constructed; S4, drilling holes for cement soil compaction piles: drilling holes between the steel pipe piles (3) to a designed depth using a diesel hammer pile driver; S5. Installation of soil compaction piles: symmetrically place the left and right symmetrical semicircular plates (401) into the hole, and then inject the filling body (403) between the left and right semicircular plates (401) under pressure, and squeeze the semicircular plates (401) to the inner wall of the hole on both sides.

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