A construction method for a tunnel in soft surrounding rock

Abstract

The present invention discloses a construction method for a tunnel in soft surrounding rock, comprising the following steps: detecting the soft surrounding rock section where the tunnel is located; excavating the soft surrounding rock section where the tunnel is located and performing pretreatment; fabricating an inverted arch formwork structure; fabricating a support structure; hoisting the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located; performing pouring treatment on the inverted arch formwork structure and the support structure; and monitoring the soft surrounding rock section where the tunnel is located during the construction stage by means of surrounding rock measurement. The technical solution of the present invention can realize a dynamic mode of construction integrating detection, construction and monitoring; thereby ensuring construction safety, quality and efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly relates to a construction method for a tunnel in soft surrounding rock. Background Technique

[0002] A tunnel is an engineering structure built underground with entrances and exits at both ends for vehicles, pedestrians, water flow, pipelines, etc. The definition of a tunnel given by the Tunnel Conference in 1970 considering various factors is: "A chamber with a cross-sectional area greater than 2 m 2 constructed underground for a certain purpose by any method with a specified shape and size." All are called tunnels. According to the length of the tunnel, tunnels are classified into extra-long tunnels (length greater than 10 Km), long tunnels (length greater than 3 Km), medium-long tunnels (length greater than 500 m), and short tunnels (length less than 500 m); according to the cross-sectional area of the tunnel excavation, tunnels are classified into extra-large cross-section tunnels (excavation area greater than 100 m 2 ), large cross-section tunnels (excavation area 50 - 100 m 2 ), medium cross-section tunnels (excavation area 10 - 50 m 2 ), and extremely small cross-section tunnels (excavation area less than 3 m 2 ).

[0003] However, most of the existing construction methods for tunnels in soft surrounding rock are prone to phenomena such as increased water pressure, continuous water accumulation, and water inrush and mud burst in the tunnels, resulting in the instability of the tunnel and inclined shaft structures; furthermore, the construction safety performance is reduced and the efficiency is not high. Summary of the Invention

[0004] The main object of the present invention is to propose a construction method for a tunnel in soft surrounding rock, aiming to improve the construction safety performance and efficiency.

[0005] The above problems to be solved by the present invention are achieved through the following technical solutions:

[0006] A construction method for a tunnel in soft surrounding rock, comprising the following steps:

[0007] Conduct geological detection on the soft surrounding rock section where the tunnel is located;

[0008] Excavate the soft surrounding rock section where the tunnel is located and perform pretreatment;

[0009] Fabricate an inverted arch formwork structure;

[0010] Fabricate a support structure;

[0011] Lift and transport the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located;

[0012] Perform pouring treatment on the inverted arch formwork structure and the support structure;

[0013] The soft surrounding rock section where the tunnel is located during the construction stage is monitored by the surrounding rock measurement method.

[0014] Preferably, the steps of excavating the soft surrounding rock section where the tunnel is located and performing pretreatment include the following steps:

[0015] Excavate the main cavity and the auxiliary cavity in the soft surrounding rock section where the tunnel is located; and an inclined first circulation channel is provided between the main cavity and the auxiliary cavity;

[0016] Drain the circulating gas to the auxiliary cavity, so that the circulating gas flows through the first circulation channel to the heading face of the main cavity;

[0017] Discharge the circulating gas from the heading face out of the main cavity.

[0018] Preferably, in the step of draining the circulating gas to the auxiliary cavity so that the circulating gas flows through the first circulation channel to the heading face of the main cavity, the following steps are included:

[0019] Guide the circulating gas in the auxiliary cavity through the first circulation channel by a first booster drainer, and transport the circulating gas to the heading face of the main cavity.

[0020] Preferably, in the step of draining the circulating gas to the auxiliary cavity so that the circulating gas flows through the first circulation channel to the heading face of the main cavity, the following steps are included:

[0021] Guide the circulating gas in the auxiliary cavity to the boundary surface of the auxiliary cavity by a second booster drainer; and the circulating gas is transported from the boundary surface of the auxiliary cavity to the heading face of the main cavity through the first circulation channel.

[0022] Preferably, the invert formwork structure includes at least one filling side formwork and at least one invert formwork; in the step of manufacturing the invert formwork structure, the following steps are included:

[0023] Manufacture the invert formwork and the filling side formwork respectively, and assemble the invert formwork and the filling side formwork into one body.

[0024] Preferably, the invert formwork includes at least one invert side wall body and at least one end formwork body; in the step of manufacturing the invert formwork and the filling side formwork respectively and assembling the invert formwork and the filling side formwork into one body, the following steps are included:

[0025] Connect the first end of the filled side formwork to the first end of the end formwork body; connect the second end of the end formwork body to the first end of the inverted arch side wall; and a transverse construction joint is provided between the second end of the end formwork body and the first end of the inverted arch side wall.

[0026] Preferably, the support structure includes at least two transverse arc skeletons, at least one longitudinal support frame, and at least one guiding arc strip; in the step of fabricating the support structure, the following steps are included:

[0027] Assemble the transverse arc skeletons, the longitudinal support frames, and the guiding arc strips to form the support structure.

[0028] Preferably, the support structure further includes at least one bottom support frame; in the step of assembling the transverse arc skeletons, the longitudinal support frames, and the guiding arc strips to form the support structure, the following steps are included:

[0029] Arrange the transverse arc skeletons side by side, and assemble the side-by-side transverse arc skeletons above the bottom support frame;

[0030] Pass the longitudinal support frames through the transverse arc skeletons respectively, so that the transverse arc skeletons and the longitudinal support frames are connected as a whole;

[0031] Connect the guiding arc strip to the outer surfaces of the transverse arc skeletons and the longitudinal support frames.

[0032] Preferably, the step of hoisting the inverted arch formwork structure and the support structure to the weak surrounding rock section where the tunnel is located includes the following steps:

[0033] Hoist the inverted arch formwork structure and the support structure to the weak surrounding rock section where the tunnel is located respectively; and install the support structure on the inverted arch formwork structure, so that the arc surface of the guiding arc strip faces the inner wall of the weak surrounding rock section where the tunnel is located.

[0034] Preferably, in the step of monitoring the weak surrounding rock section where the tunnel is located during the construction stage by the surrounding rock measurement method, the following steps are included:

[0035] Monitor the structural layer condition of the weak surrounding rock section, the pouring condition of the inverted arch formwork structure, and the supporting condition of the support structure in the weak surrounding rock section where the tunnel is located during the construction stage through the formation acoustic CT detection technology.

[0036] Beneficial effects: The technical solution of the present invention first detects the soft surrounding rock geology where the tunnel is located, realizes the preliminary analysis of the soft surrounding rock geology where the tunnel is located, ensures the subsequent safe construction according to the analysis situation, and thus lays a foundation for the quality and stability of the subsequent construction; then excavates the soft surrounding rock section where the tunnel is located and conducts pretreatment, and further ensures the construction stability by preprocessing the excavation section; then respectively fabricates the inverted arch formwork structure and the support structure, hoists the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located, and then conducts pouring treatment on the inverted arch formwork structure and the support structure, so as to realize the construction support for the bottom of the soft surrounding rock section through the inverted arch structure and the construction support for the side and top of the soft surrounding rock section through the support structure; finally, monitors the soft surrounding rock section where the tunnel is located during the construction stage by the surrounding rock measurement method; thus realizing the dynamic mode construction of the trinity of detection, construction and monitoring; and further ensuring the construction safety, quality and efficiency. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0038] Figure 1 It is a flowchart of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0039] Figure 2 It is a flowchart of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0040] Figure 3 It is a flowchart of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0041] Figure 4 It is a ventilation schematic diagram of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0042] Figure 5 It is a pouring schematic diagram of an inverted arch formwork structure of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0043] Figure 6 It is a diversion schematic diagram of a support structure of an embodiment of a construction method for a tunnel in soft surrounding rock according to the present invention.

[0044] Explanation of the reference numerals in the drawings:

[0045] Specific implementation manners

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0048] In addition, if the descriptions such as "first" and "second" are involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0049] The present invention provides a construction method for a tunnel in soft surrounding rock.

[0050] As Figure 1 shown, in an embodiment of the present invention, the construction method for a tunnel in soft surrounding rock includes the following steps:

[0051] S1. Conduct geological detection on the soft surrounding rock section where the tunnel is located;

[0052] S2. Excavate the soft surrounding rock section where the tunnel is located and perform pretreatment;

[0053] S3. Fabricate an inverted arch formwork structure;

[0054] S4. Fabricate a support structure;

[0055] S5. Hoist the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located;

[0056] S6. Pour the inverted arch formwork structure and the support structure.

[0057] S7. Monitor the weak surrounding rock section where the tunnel is located during the construction stage by means of surrounding rock measurement.

[0058] The technical solution of the present invention first conducts geological detection on the weak surrounding rock section where the tunnel is located to realize the preliminary analysis of the geology of the weak surrounding rock where the tunnel is located, and ensures the subsequent safe construction according to the analysis situation, thereby laying a foundation for the quality and stability of the subsequent construction; then excavates the weak surrounding rock section where the tunnel is located and conducts pre-treatment. By pre-treating the excavated section, the construction stability can be further guaranteed; then the inverted arch formwork structure and the support structure are respectively fabricated, and the inverted arch formwork structure and the support structure are hoisted to the weak surrounding rock section where the tunnel is located. Then, the inverted arch formwork structure and the support structure are poured, so as to realize the construction support of the bottom of the weak surrounding rock section through the inverted arch structure and the construction support of the side and top of the weak surrounding rock section through the support structure; finally, the weak surrounding rock section where the tunnel is located during the construction stage is monitored by means of surrounding rock measurement; thus, a dynamic mode construction of the trinity of detection, construction and monitoring is realized; furthermore, the construction safety, quality and efficiency are guaranteed.

[0059] Among them, weak surrounding rock is also called host rock and ore-bearing rock; and in rock underground engineering, it is the surrounding rock mass in the weak surrounding area where the stress state changes due to excavation. Its geological structural plane is well developed, the rock mass is extremely fragmented, almost loose, and most of the rock masses in the interlayer fracture zone, large-scale faults or strongly weathered areas show such characteristics.

[0060] Specifically, in some embodiments, in S1, in the step of conducting geological detection on the weak surrounding rock section where the tunnel is located, the following are included:

[0061] Detect the structural layering situation, looseness situation, water gushing section situation and stress-bearing capacity situation of the weak surrounding rock section where the tunnel is located. Through the detection and analysis of several major coefficients of the weak surrounding rock section where the tunnel is located, the detection and analysis before construction can be realized, which lays a foundation for the design of the subsequent inverted arch formwork structure, support structure and other auxiliary structures, and guarantees the construction stability and efficiency.

[0062] Specifically, in some embodiments, as Figure 3 and 4 shown, in S2, the step of excavating the weak surrounding rock section where the tunnel is located and conducting pre-treatment includes the following steps:

[0063] S21. Excavate the main tunnel body 1 and the auxiliary tunnel body 2 in the soft surrounding rock section where the tunnel is located; and an inclined first circulation passage 5 is provided between the main tunnel body 1 and the auxiliary tunnel body 2; wherein, in some embodiments, after excavating the main tunnel body 1, the auxiliary tunnel body 2 and the first circulation passage 5, clean the interiors of the main tunnel body 1, the auxiliary tunnel body 2 and the first circulation passage 5; wherein, in some embodiments, the main tunnel body 1 and the auxiliary tunnel body 2 are arranged in parallel.

[0064] S22. Drain the circulating gas to the auxiliary tunnel body 2.

[0065] S231. Guide the circulating gas in the auxiliary tunnel body 2 through the first pressurized drainage device 62 along the first circulation passage 5, and transport the circulating gas to the heading face 3 of the main tunnel body 1; and / or, S232. Guide the circulating gas in the auxiliary tunnel body 2 to the boundary surface 21 of the auxiliary tunnel body 2 through the second pressurized drainage device 61; and the circulating gas is transported from the boundary surface 21 of the auxiliary tunnel body 2 along the first circulation passage 5 to the heading face 3 of the main tunnel body 1.

[0066] S24. Discharge the circulating gas from the heading face 3 out of the main tunnel body 1. Ventilate the main tunnel body by excavating the main tunnel body 1 and the auxiliary tunnel body 2 and using the first circulation passage 5; in one way, the circulating gas is guided from the auxiliary tunnel body through the first circulation passage to the heading face for ventilation and air exchange by the first pressurized drainage device 62, which can ensure the quality of the circulating gas during construction at the heading face and increase the oxygen concentration; in another way, after the circulating gas flows to the boundary surface through the second pressurized drainage device 61, it rebounds and is guided through the first circulation passage to the heading face, which can achieve guiding the circulating gas in the auxiliary tunnel body to the heading face as much as possible, improve the ventilation and air exchange efficiency and the oxygen concentration quality at the heading face, and ensure construction safety; in yet another embodiment, the circulating gas is guided from the auxiliary tunnel body through the first circulation passage to the heading face for ventilation and air exchange by the first pressurized drainage device 62, and at the same time, the circulating gas flows to the boundary surface through the second pressurized drainage device 61 and then rebounds and is guided through the first circulation passage to the heading face for two-way transportation of circulating air exchange, further improving the ventilation and air exchange efficiency and the oxygen concentration quality at the heading face and ensuring construction safety; and, the ventilation and air exchange efficiency and the oxygen concentration quality in the third way are better than the first two.

[0067] Wherein, in some embodiments, both the first pressurized drainage device 62 and the second pressurized drainage device 61 are axial flow fans.

[0068] Wherein, the boundary surface 21 refers to the boundary surface opposite to the circulating gas inlet of the auxiliary tunnel body 2.

[0069] Specifically, in some embodiments, such as Figure 2 and 5 shown, the invert formwork structure includes at least one filling side formwork 91 and at least one invert formwork 92; in the step S3 of manufacturing the invert formwork structure, the following steps are included:

[0070] Manufacture the invert formwork and the filling side formwork respectively, and assemble the invert formwork and the filling side formwork into one body.

[0071] Among them, in some embodiments, the invert formwork 92 includes at least one invert side wall 922 and at least one end formwork body 921; in the step of manufacturing the invert formwork and the filling side formwork respectively and assembling the invert formwork and the filling side formwork into one body, the following steps are included:

[0072] Splice and connect the first end of the filling side formwork 91 with the first end of the end formwork body 921; splice and connect the second end of the end formwork body 921 with the first end of the invert side wall 922; and a transverse construction joint 920 is provided between the second end of the end formwork body 921 and the first end of the invert side wall 922. By assembling the invert formwork and the end formwork body into one body; then assembling the filling side formwork and the end formwork body to form a whole, so that a seamless joint after one-time formwork erection can be achieved, and then an integral invert structure can be obtained, ensuring its structural stability and laying a foundation for the quality and stability of subsequent construction.

[0073] Specifically, in some embodiments, such as Figure 2 and 6 shown, the support structure includes at least two transverse arc skeletons 82, at least one longitudinal support frame 83 and at least one guiding arc strip 7; in the step S4 of manufacturing the support structure, the following steps are included:

[0074] Assemble the transverse arc skeletons, the longitudinal support frames and the guiding arc strips to form the support structure.

[0075] Among them, in some embodiments, the support structure further includes at least one bottom support frame 81; in the step of assembling the transverse arc skeletons, the longitudinal support frames and the guiding arc strips to form the support structure, the following steps are included:

[0076] Arrange the transverse arc skeletons side by side, and assemble the arranged transverse arc skeletons above the bottom support frame;

[0077] Pass the longitudinal support frames through the transverse arc skeletons respectively, so that the transverse arc skeletons and the longitudinal support frames are connected into one body;

[0078] Connect the guiding arc strip to the outer surfaces of the transverse arc framework and the longitudinal support frame.

[0079] Specifically, in some embodiments, as Figure 2 shown, in step S5, the step of hoisting the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located includes the following steps:

[0080] Hoist the inverted arch formwork structure and the support structure to the soft surrounding rock section where the tunnel is located respectively; and install the support structure on the inverted arch formwork structure so that the arc surface of the guiding arc strip faces the inner wall of the soft surrounding rock section where the tunnel is located.

[0081] Perform pre-support treatment through the guiding arc strip and the water gushing section in the soft surrounding rock section where the tunnel is located, so as to achieve targeted treatment of the support structure, effectively reduce the groundwater and local water pressure behind the lining, and avoid the failure of the initial shotcrete.

[0082] Specifically, in some embodiments, in step S7, the step of monitoring the soft surrounding rock section where the tunnel is located during the construction stage by the surrounding rock measurement method includes the following steps:

[0083] Monitor the structural layer condition of the soft surrounding rock section, the pouring condition of the inverted arch formwork structure, and the support condition of the support structure in the soft surrounding rock section where the tunnel is located during the construction stage through the formation acoustic CT detection technology.

[0084] Among them, since existing advanced geological forecasts mostly use new tunnel three-dimensional geological forecasting technologies such as ground penetrating radar, infrared detection, TSP, etc. to predict soft surrounding rock in front of the heading face. The prediction distances of ground penetrating radar and infrared detection are both short and the accuracy is low. The TSP prediction distance is longer but it only predicts soft surrounding rock in front of the heading face, and the prediction accuracy of the soft surrounding rock situation around the tunnel cannot visually and accurately judge the location and scope of bad geology and the size of the water inflow. Among them, in this embodiment, the formation acoustic CT detection technology is realized by using a formation acoustic CT detector; and the formation acoustic CT detector is mainly applied to formation, bad geology detection and engineering quality inspection, uses digital multi-elements and combines with normal tunnel geological forecasting to accurately predict bad geological conditions, achieve long-distance forecasting, long-distance water exploration, three-dimensional space stereoscopic imaging, quickly and accurately predict the location of bad geology and the water inflow; perform theoretical verification after the excavation is completed.

[0085] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A construction method for a tunnel in soft surrounding rock, characterized in that It includes the following steps: Conduct geological detection on the soft surrounding rock section where the tunnel is located; Excavate the soft surrounding rock section where the tunnel is located and conduct pre-treatment; Fabricate an invert formwork structure; Fabricate a support structure; Lift and transport the invert formwork structure and the support structure to the soft surrounding rock section where the tunnel is located; Conduct pouring treatment on the invert formwork structure and the support structure; Monitor the soft surrounding rock section where the tunnel is located during the construction stage through the surrounding rock measurement method; The invert formwork structure includes at least one filling side formwork and at least one invert formwork; In the step of fabricating the invert formwork structure, it includes the following steps: Fabricate the invert formwork and the filling side formwork respectively, and assemble the invert formwork and the filling side formwork into one body; The invert formwork includes at least one invert side wall body and at least one end formwork body; in the step of fabricating the invert formwork and the filling side formwork respectively and assembling the invert formwork and the filling side formwork into one body, it includes the following steps: Splice and connect the first end of the filling side formwork with the first end of the end formwork body; splice and connect the second end of the end formwork body with the first end of the invert side wall body; and a transverse construction joint is provided between the second end of the end formwork body and the first end of the invert side wall body; The support structure includes at least two transverse arc skeletons, at least one longitudinal support frame and at least one guiding arc strip; in the step of fabricating the support structure, it includes the following steps: Assemble the transverse arc skeletons, the longitudinal support frames and the guiding arc strips to form the support structure; The step of lifting and transporting the invert formwork structure and the support structure to the soft surrounding rock section where the tunnel is located includes the following steps: Lift and transport the invert formwork structure and the support structure to the soft surrounding rock section where the tunnel is located respectively; and install the support structure on the invert formwork structure so that the arc surface of the guiding arc strip faces the inner wall of the soft surrounding rock section where the tunnel is located.

2. The construction method of a soft surrounding rock tunnel according to claim 1, characterized in that, The step of excavating the soft surrounding rock section where the tunnel is located and conducting pre-treatment includes the following steps: Excavate the main tunnel body and the auxiliary tunnel body in the soft surrounding rock section where the tunnel is located; and an inclined first circulation channel is provided between the main tunnel body and the auxiliary tunnel body; Drain the circulating gas to the auxiliary tunnel body so that the circulating gas flows through the first circulation channel to the face of the main tunnel body; Discharge the circulating gas from the face out of the main tunnel body.

3. A construction method for a tunnel in soft surrounding rock according to claim 2, characterized in that, In the step of draining the circulating gas to the auxiliary tunnel body so that the circulating gas flows through the first circulation channel to the face of the main tunnel body, it includes the following steps: Guide the circulating gas through the first circulation channel by a first booster drainer and transport the circulating gas to the face of the main tunnel body.

4. A construction method for a tunnel in soft surrounding rock according to claim 2 or 3, characterized in that In the step of draining the circulating gas to the auxiliary tunnel body so that the circulating gas flows through the first circulation channel to the face of the main tunnel body, it includes the following steps: The circulating gas is guided to the boundary surface of the auxiliary cavity through the second booster drainer; and the circulating gas is transported from the boundary surface of the auxiliary cavity to the heading face of the main cavity through the first circulation channel.

5. A construction method for a tunnel in soft surrounding rock according to claim 1, characterized in that, The support structure further includes at least one bottom support frame; in the step of assembling the transverse arc frame, the longitudinal support frame and the guiding arc strip to form the support structure, the following steps are included: Distribute the transverse arc frames side by side, and assemble the side-by-side transverse arc frames above the bottom support frame; Pass the longitudinal support frames through the transverse arc frames respectively so that the transverse arc frames and the longitudinal support frames are connected into one body; Connect the guiding arc strip to the outer surfaces of the transverse arc frame and the longitudinal support frame.

6. The construction method of a soft surrounding rock tunnel according to claim 1, characterized in that In the step of monitoring the soft surrounding rock section where the tunnel is located during the construction stage by the surrounding rock measurement method, the following steps are included: Monitor the structural layer condition of the soft surrounding rock section, the pouring condition of the inverted arch formwork structure and the supporting condition of the support structure in the soft surrounding rock section where the tunnel is located during the construction stage by the formation acoustic CT detection technology.

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