Composite stratum support method and support structure

Abstract

The present invention relates to the technical field of tunnel support, and provides a composite stratum support method, comprising the following steps: constructing a pipe curtain steel pipe in a soft stratum, and one end of the pipe curtain steel pipe is constructed to the interface between the soft stratum and the hard stratum; adjacent pipe curtain steel pipes are interlocked together through locking joints; cement mortar is poured into the pipe curtain steel pipe and the locking joint, and a pipe curtain grouting body is formed after the cement mortar solidifies; a pipe roof steel pipe is constructed in the pipe curtain grouting body in the pipe curtain steel pipe; one end of the pipe roof steel pipe passes through the interface between the soft stratum and the hard stratum and is drilled to a predetermined position in the hard stratum; cement mortar is poured into the pipe roof steel pipe, and a pipe roof grouting body is formed after the cement mortar solidifies. The composite stratum support method provided by the embodiment of the present invention avoids the occurrence of a support weak zone at the interface between the soft stratum and the hard stratum, and improves the support effect at the junction of the soft stratum and the hard stratum.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel support, in particular to a composite stratum support method and a support structure. Background Art

[0002] At present, pipe curtains and pipe sheds are widely used as advance support measures in tunnel advance support construction.

[0003] The pipe curtain is a steel pipe curtain structure pre-formed in the stratum by densely arranging large diameter steel pipes and connecting them together through locking buckles. It has the advantages of high rigidity, good water-stopping effect, strong anti-deformation ability, safe and reliable construction, etc. It is suitable for soft strata, but has poor applicability to hard strata, such as medium and slightly weathered rock strata.

[0004] The pipe roof is a steel pipe roof protective structure formed in the stratum in advance by various types of steel pipes at intervals, and the steel pipes do not bite each other. It has the advantages of flexible construction, safe and reliable construction, etc. It is suitable for hard strata that do not require too much bearing capacity and do not require water-stopping. It is not suitable for soft strata that require large bearing capacity and need water-stopping.

[0005] Composite strata refer to strata composed of two or more different strata within the excavation section of underground engineering and in the excavation extension direction, and these strata have very different characteristics in geotechnical mechanics, engineering geology and hydrogeology. For the advance support in composite strata, the effect of using pipe curtain or pipe shed alone is poor; therefore, pipe curtain and pipe shed are often used together for advance support of composite strata.

[0006] Figure 1 A kind of advanced support structure in composite stratum is shown in FIG. Figure 1 , a pipe curtain steel pipe 12 and a pipe roof steel pipe 13 are constructed from left to right in the soft stratum 10; wherein the right end of the pipe curtain steel pipe 12 is constructed to the interface 14 between the soft stratum 10 and the hard stratum 11, and the right end of the pipe roof steel pipe 13 passes through the interface 14 between the soft stratum 10 and the hard stratum 11 and extends to a predetermined position in the hard stratum 11.

[0007] Although the above-mentioned support method can provide advance support for the composite stratum through the support structure composed of the pipe curtain and the pipe shed, at the interface 13 between the soft stratum 10 and the hard stratum 11, Figure 1 At point A indicated by the middle dotted line, a weak support area is likely to appear, resulting in poor support effect; during the subsequent tunnel excavation process, groundwater in the soft stratum is likely to flow from point A into the tunnel, affecting the safety of tunnel construction. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a composite stratum support method and a support structure to improve the support effect at the junction of soft strata and hard strata.

[0009] The technical solution adopted by the present invention to solve the technical problem is: a composite stratum support method, comprising the following steps:

[0010] S1. Construct the pipe curtain steel pipe in the soft stratum, and one end of the pipe curtain steel pipe is constructed to the interface between the soft stratum and the hard stratum; the adjacent pipe curtain steel pipes are interlocked together through locking joints;

[0011] S2. Pour cement mortar into the pipe curtain steel pipe and the lock joint, and form a pipe curtain grouting body after the cement mortar solidifies;

[0012] S3, constructing a pipe-roof steel pipe in the pipe-roof grouting body in the pipe-roof steel pipe; one end of the pipe-roof steel pipe passes through the interface between the soft stratum and the hard stratum and is drilled to a predetermined position in the hard stratum;

[0013] S4. Pour cement mortar into the steel pipe of the pipe-roof, and form a pipe-roof grouting body after the cement mortar solidifies.

[0014] Furthermore, a plurality of pipe curtain grouting through holes are arranged on the pipe wall of the pipe curtain steel pipe.

[0015] Furthermore, a plurality of pipe-roof grouting through holes are provided on the pipe wall of the pipe-roof steel pipe.

[0016] A composite stratum support structure comprises a pipe curtain steel pipe and a pipe roof steel pipe; the pipe curtain steel pipe is arranged in a soft stratum, and one end of the pipe curtain steel pipe extends to the interface between the soft stratum and the hard stratum; adjacent pipe curtain steel pipes are interlocked together through locking joints; a pipe curtain grouting body is cast in the pipe curtain steel pipe and the locking joints; the pipe roof steel pipe is arranged in the pipe curtain grouting body in the pipe curtain steel pipe, and one end of the pipe roof steel pipe passes through the interface between the soft stratum and the hard stratum and extends to the hard stratum; the pipe roof grouting body is cast in the pipe roof steel pipe.

[0017] Furthermore, a pipe curtain grouting through hole is provided on the pipe wall of the pipe curtain steel pipe.

[0018] Furthermore, a pipe-roof grouting through hole is provided on the pipe wall of the pipe-roof steel pipe.

[0019] The beneficial effects of the present invention are as follows: the composite stratum support method and support structure provided by the embodiment of the present invention construct a pipe-roof steel pipe in the pipe-roof grouting body inside the pipe-roof steel pipe, and allow one end of the pipe-roof steel pipe to pass through the interface between the soft stratum and the hard stratum and extend to a predetermined position in the hard stratum. In this way, not only the pipe roof is supported by the pipe curtain in the soft stratum, but the pipe curtain and the pipe roof are firmly connected together. At the same time, the appearance of a support weak zone at the interface between the soft stratum and the hard stratum is avoided, thereby improving the support effect at the junction of the soft stratum and the hard stratum; in the subsequent tunnel excavation process, groundwater is prevented from flowing into the tunnel from the junction of the soft stratum and the hard stratum, thereby improving the safety of tunnel construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below; obviously, the drawings described below are only some embodiments recorded in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the existing support structure in the composite stratum;

[0022] Figure 2 It is a state diagram after the pipe curtain is constructed in the composite stratum support method provided by an embodiment of the present invention;

[0023] Figure 3 yes Figure 2 Cross-sectional view of the middle pipe curtain after construction;

[0024] Figure 4 It is a state diagram after the pipe roof is constructed in the composite stratum support method provided by an embodiment of the present invention;

[0025] Figure 5 yes Figure 4 Cross-sectional view of the middle pipe shed after construction.

[0026] The reference numerals in the figure are: 10-soft formation, 11-hard formation, 12-pipe curtain steel pipe, 13-pipe roof steel pipe, 14-interface; 101-pipe curtain steel pipe, 102-pipe roof steel pipe, 103-soft formation, 104-hard formation, 105-interface, 106-locking joint, 107-pipe curtain grouting body, 108-pipe roof grouting body, 109-pipe curtain grouting through hole, 110-pipe roof grouting through hole. DETAILED DESCRIPTION

[0027] In order to make those skilled in the art better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0028] See also Figures 2 to 5 The composite stratum support method provided by the embodiment of the present invention comprises the following steps:

[0029] S1. constructing a pipe-roof steel pipe 101 in a soft stratum 103, and constructing one end of the pipe-roof steel pipe 101 to the interface 105 between the soft stratum 103 and the hard stratum 104; adjacent pipe-roof steel pipes 101 are interlocked together by means of a locking joint 106;

[0030] S2, pouring cement mortar into the pipe-roof steel pipe 101 and the lock joint 106, and forming a pipe-roof grouting body 107 after the cement mortar solidifies;

[0031] S3, constructing a pipe-roof steel pipe 102 in the pipe-roof grouting body 107 in the pipe-roof steel pipe 101; one end of the pipe-roof steel pipe 102 passes through the interface 105 between the soft stratum 103 and the hard stratum 104 and is drilled to a predetermined position in the hard stratum 104;

[0032] S4. Pour cement mortar into the pipe-roof steel pipe 102, and form a pipe-roof grouting body 108 after the cement mortar solidifies.

[0033] In step S1, see Figure 2 , construct a pipe curtain working pit (not shown in the figure), and the construction personnel use the traditional pipe curtain construction technology in the pipe curtain working pit to construct the pipe curtain steel pipes 101 from left to right one by one into the soft formation 103, and the right end of the pipe curtain steel pipe 101 is constructed to the interface 105 between the soft formation 103 and the hard formation 104. Among them, the adjacent pipe curtain steel pipes 101 are interlocked together by locking joints 106; for details, see Figure 3 A male joint and a female joint are respectively provided on the left and right sides of each pipe curtain steel pipe 101. Adjacent pipe curtain steel pipes 101 are interlocked together through a locking joint 106 composed of a male joint and a female joint, and the male joint can move axially in the female joint along the pipe curtain steel pipe 101.

[0034] In step S2, cement mortar is poured into the pipe curtain steel pipe 101 and the locking joint 106 using a grouting tool. After the cement mortar is solidified, a pipe curtain grouting body 107 is formed in the pipe curtain steel pipe 101 and the locking joint 106. In this way, the single pipe curtain steel pipe 101 is transformed from a hollow tube into a steel tube concrete beam, thereby increasing the direct load-bearing capacity of the single pipe curtain steel pipe 101.

[0035] For further information, see Figure 3 , a plurality of pipe curtain grouting through holes 109 are arranged on the pipe wall of the pipe curtain steel pipe 101. When cement mortar is poured into the pipe curtain steel pipe 101, the cement mortar can penetrate into the surrounding rock of the soft stratum 103 along the pipe curtain grouting through holes 109 of the pipe curtain steel pipe 101 to a certain extent to fill the cracks in the surrounding rock; after the cement mortar solidifies, all the pipe curtain steel pipes 101 are united with the surrounding rock to form an integral annular bearing ring, so that the surrounding rock in the soft stratum 103 is reinforced and the self-stabilizing ability of the surrounding rock after excavation is improved.

[0036] In step S3, see Figure 4 The construction personnel use a self-drilling pipe-roof machine in the pipe-roof working well to construct the pipe-roof steel pipe 102 from left to right into the pipe-roof grouting body 107 in the pipe-roof steel pipe 101. After the pipe-roof steel pipe 102 is constructed to the end of the pipe-roof grouting body 107, it further passes through the interface 105 between the soft stratum 103 and the hard stratum 104 and drills into a predetermined position in the hard stratum 104. Among them, one pipe-roof steel pipe 102 can be constructed in the pipe-roof grouting body 107 in each pipe-roof steel pipe 101, or two or more pipe-roof steel pipes 102 can be constructed, which is not specifically limited here.

[0037] In step S4, cement mortar is poured into the pipe-roof steel pipe 102 using a grouting tool. After the cement mortar is solidified, a pipe-roof grouting body 108 is formed in the pipe-roof steel pipe 102. In this way, a single pipe-roof steel pipe 102 is transformed from a hollow pipe into a steel pipe concrete beam, thereby increasing the direct load-bearing capacity of the single pipe-roof steel pipe 102.

[0038] For further information, see Figure 5 , a plurality of pipe-roof grouting through holes 110 are arranged on the pipe wall of the pipe-roof steel pipe 102. When cement mortar is poured into the pipe-roof steel pipe 102, the cement mortar can penetrate into the gap between the pipe-roof steel pipe 102 and the pipe-roof grouting body 107 and the surrounding rock of the hard formation 104 along the pipe-roof grouting through holes 110 of the pipe-roof steel pipe 102 to a certain extent, so as to fill the gap between the pipe-roof steel pipe 102 and the pipe-roof grouting body 107 and the surrounding rock cracks in the hard formation 104; after the cement mortar solidifies, the pipe-roof steel pipe 102 can be firmly connected to the pipe-roof grouting body 107 and the rock mass in the hard formation 104, respectively, thereby improving the reliability of the support structure.

[0039] The composite stratum support method provided in the embodiment of the present invention can support the soft stratum 103 through the pipe curtain through steps S1 and S2; through steps S3 and S4, not only the hard stratum 104 is supported by the pipe shelf, but also the pipe curtain and the pipe shelf are firmly connected together, so as to avoid the appearance of a support weak area at the interface 105 between the soft stratum 103 and the hard stratum 104, thereby improving the support effect at the junction of the soft stratum 103 and the hard stratum 104; in the subsequent tunnel excavation process, groundwater is prevented from flowing into the tunnel from the junction of the soft stratum 103 and the hard stratum 104, thereby improving the safety of tunnel construction.

[0040] See also Figure 4 , Figure 5 The composite stratum support structure provided by the embodiment of the present invention comprises a pipe curtain steel pipe 101 and a pipe roof steel pipe 102; the pipe curtain steel pipe 101 is arranged in a soft stratum 103, and one end thereof extends to the interface 105 between the soft stratum 103 and the hard stratum 104; adjacent pipe curtain steel pipes 101 are interlocked together by a locking joint 106; a pipe curtain grouting body 107 is poured in the pipe curtain steel pipe 101 and the locking joint 106; the pipe roof steel pipe 102 is arranged in the pipe curtain grouting body 107 in the pipe curtain steel pipe 101, and one end of the pipe roof steel pipe 102 passes through the interface 105 between the soft stratum 103 and the hard stratum 104 and extends to the hard stratum 104; a pipe roof grouting body 108 is poured in the pipe roof steel pipe 102. Furthermore, a pipe curtain grouting through hole 109 is arranged on the pipe wall of the pipe curtain steel pipe 101. A pipe-roof grouting through hole 110 is provided on the pipe wall of the pipe-roof steel pipe 102 .

[0041] The composite stratum support structure provided by the embodiment of the present invention constructs a pipe-roof steel pipe 102 in a pipe-roof grouting body 107 in a pipe-roof steel pipe 101, and allows one end of the pipe-roof steel pipe 102 to pass through an interface 105 between a soft stratum 103 and a hard stratum 104 and extend to a predetermined position in the hard stratum 104. In this way, the pipe roof is not only supported by the pipe roof in the soft stratum 103, but also the pipe roof and the pipe roof are firmly connected together. At the same time, the appearance of a support weak zone at the interface 105 between the soft stratum 103 and the hard stratum 104 is avoided, thereby improving the support effect at the junction 105 between the soft stratum 103 and the hard stratum 104. In the subsequent tunnel excavation process, groundwater is prevented from flowing into the tunnel from the junction of the soft stratum and the hard stratum, thereby improving the safety of tunnel construction.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite stratum support method, characterized in that: The steps include: S1. constructing a pipe curtain steel pipe (101) in a soft stratum (103), and constructing one end of the pipe curtain steel pipe (101) to the interface (105) between the soft stratum (103) and the hard stratum (104); adjacent pipe curtain steel pipes (101) are interlocked together through locking joints (106); S2, pouring cement mortar into the pipe curtain steel pipe (101) and the lock joint (106), and forming a pipe curtain grouting body (107) after the cement mortar solidifies; S3, constructing a pipe-roof steel pipe (102) in a pipe-roof grouting body (107) inside a pipe-roof steel pipe (101); one end of the pipe-roof steel pipe (102) passes through an interface (105) between a soft stratum (103) and a hard stratum (104) and is drilled to a predetermined position in the hard stratum (104); S4, pouring cement mortar into the pipe-roof steel pipe (102), and forming a pipe-roof grouting body (108) after the cement mortar solidifies.

2. The composite stratum support method according to claim 1, characterized in that: A plurality of pipe curtain grouting through holes (109) are arranged on the pipe wall of the pipe curtain steel pipe (101).

3. The composite stratum support method according to claim 1 or 2, characterized in that: A plurality of pipe-roof grouting through holes (110) are arranged on the pipe wall of the pipe-roof steel pipe (102).

4. A composite ground support structure, comprising a pipe-roof steel pipe (101) and a pipe-roof steel pipe (102); characterized in that: The pipe curtain steel pipe (101) is arranged in a soft stratum (103), and one end thereof extends to the interface (105) between the soft stratum (103) and the hard stratum (104); adjacent pipe curtain steel pipes (101) are interlocked together through a locking joint (106); a pipe curtain grouting body (107) is poured in the pipe curtain steel pipe (101) and the locking joint (106); The pipe-roof steel pipe (102) is arranged in a pipe-roof grouting body (107) inside a pipe-roof steel pipe (101), and one end of the pipe-roof steel pipe (102) passes through an interface (105) between a soft stratum (103) and a hard stratum (104) and extends into the hard stratum (104); a pipe-roof grouting body (108) is poured inside the pipe-roof steel pipe (102).

5. The composite stratum support structure according to claim 4, characterized in that: A pipe curtain grouting through hole (109) is provided on the pipe wall of the pipe curtain steel pipe (101).

6. The composite stratum support structure according to claim 4 or 5, characterized in that: A pipe-roof grouting through hole (110) is provided on the pipe wall of the pipe-roof steel pipe (102).

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