A shield tunnel portal structure system and construction method constructed using a slope method

Abstract

The present invention relates to the technical field of shield tunneling, and more particularly to a shield tunnel portal structure system and construction method constructed using a slope method, comprising a shield launching structure and a shield receiving structure, wherein the shield launching structure comprises a back wall, a portal sleeve base, and a portal sleeve, wherein the portal sleeve is arranged on the portal sleeve base, wherein the front end of the portal sleeve is pre-embedded with embedded parts, and the rear end abuts against the side slope of the shield launching shaft foundation pit; wherein the portal sleeve is filled with plain concrete, and the front end surface of the plain concrete is parallel to the cutterhead surface of the shield machine; wherein the back wall is arranged opposite to the portal sleeve base, and one side of the back wall is arranged vertically, and the other side abuts against the side slope of the shield launching shaft foundation pit. Under the conditions of the shield launching shaft constructed using the slope method, the present invention can avoid uneven force on the cutterhead when the shield machine passes through the side slope of the shield launching shaft foundation pit by arranging the back wall, the portal sleeve base, the portal sleeve, and filling the portal sleeve with plain concrete, thereby ensuring that the shield machine can implement the shield launching safely and efficiently.

Description

Technical Field

[0001] The present invention relates to the technical field of shield tunnels, and in particular to a shield shaft portal structure system constructed using a slope method and a construction method. Background Art

[0002] With the rapid development of shield tunneling technology in my country, its construction safety and reliability, project cost, construction schedule, labor protection and other aspects have significant advantages over mining tunneling. The use of shield tunneling is becoming more and more common in various industries.

[0003] The existing technology requires the construction of shield tunnels to set up shield starting shafts and receiving shafts. The shield shafts are constructed using the open-cut method. Figure 1 As shown, excavation of the foundation pit is carried out with the retaining structure 1 providing support. The main shield shaft structure 2 is constructed of reinforced concrete. Before the shield machine is launched or arrives, the main shield shaft portal end wall 3 must be completed. A preliminary shield portal ring beam 4 is installed on the end wall (it can also be constructed directly on the retaining structure). Pre-embedded shield portal components are embedded in this ring beam to ensure safety and watertightness during the launch or arrival of the shield machine. To ensure balanced cutterhead thrust during launch and arrival, the portal end wall is constructed parallel to the cutterhead surface.

[0004] When the shield shaft is constructed using the slope method, and after the shield construction is completed, it is planned to backfill the shield shaft without constructing the main structure of the shield shaft, the starting end and the receiving end are on the same slope. In this case, if appropriate measures are not taken and the shield machine is directly pushed through the slope, the following problems will arise: (1) When the shield machine breaks through the slope, the gap between the shield cutter head and the segments will become a channel for groundwater and soil loss, which is detrimental to the stability of the slope and construction safety; (2) The thrust of the shield machine and the disturbance of the surrounding soil during the shield machine excavation process can easily destroy the stability of the foundation pit slope; (3) When the shield machine is crossing the slope, the thickness of the soil in front of the shield machine cutter head is uneven, and the shield machine cutter head is unevenly stressed, resulting in low shield machine working efficiency.

[0005] Therefore, under the conditions of shield shaft construction using the slope method, it is necessary to provide a reasonable and feasible shield shaft portal structure system and construction method in order to solve the problems faced by shield launching and receiving, and to implement shield launching and receiving safely and efficiently. Summary of the Invention

[0006] The purpose of the present invention is to provide a shield shaft portal structure system and construction method for slope method construction, which can safely and efficiently implement shield starting and receiving under the shield shaft conditions constructed by the slope method.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is a shield shaft portal structure system constructed by the slope method, including a shield starting structure and a shield receiving structure, the shield starting structure including a back wall, a portal sleeve base and a portal sleeve, the portal sleeve is arranged on the portal sleeve base, the front end of the portal sleeve is pre-embedded with embedded parts, and the rear end is against the slope of the shield starting shaft foundation pit; the portal sleeve is filled with plain concrete, and the front end surface of the plain concrete is parallel to the cutter head surface of the shield machine; the back wall is arranged opposite to the portal sleeve base, and one side of the back wall is arranged vertically, and the other side is against the slope of the shield starting shaft foundation pit.

[0008] Furthermore, a cutterhead compartment is reserved between the front end surface of the plain concrete and the front end surface of the portal sleeve.

[0009] Furthermore, when the shield machine cutterhead enters the cutterhead chamber and contacts the front end surface of the plain concrete, the tail end of the shield machine cutterhead is out of contact with the tunnel portal water-stop rubber curtain.

[0010] Furthermore, a bottom plate is provided on the bottom surface of the shield starting shaft foundation pit, and the portal sleeve base and the portal sleeve are both provided on the bottom plate.

[0011] Furthermore, the shield receiving structure includes core soil located in the shield arrival shaft, and the core soil completely covers the shield machine reaching a preset position in the shield arrival shaft and is higher than a certain height.

[0012] Furthermore, the core soil is the soil that has not been excavated when the shield reaches the bottom of the well foundation pit.

[0013] The present invention also provides a construction method for a shield tunnel portal structure system constructed by a slope method. The construction method for shield starting is as follows: using the slope method to excavate the shield starting shaft foundation pit to the pit bottom, constructing a back wall, a tunnel portal sleeve base and a tunnel portal sleeve, and pre-embedded parts necessary for shield starting at the front end of the tunnel portal sleeve; before the shield starts, filling the tunnel portal sleeve with plain concrete, the front end face of the plain concrete is parallel to the shield machine cutter head face, and a cutter head bin is reserved between the front end face of the plain concrete and the front end face of the tunnel portal sleeve; after the shield machine is hoisted into place, the tunnel portal water-stop rubber curtain is fixed to the tunnel portal sleeve through the pre-embedded parts. At the front end, when the shield machine cutterhead enters the cutterhead chamber and contacts the front end surface of the plain concrete, the tail of the shield machine cutterhead is out of contact with the water-stop rubber curtain of the tunnel portal, and then the shield machine breaks the plain concrete to complete the shield start; the construction method of shield reception is: use the slope method to excavate the shield arrival well, retain stable core soil before the shield machine reaches the tunnel portal, and stop the shield machine after it excavates until it pushes the shield machine to reach the slope of the well foundation pit. After completing the grouting and consolidation behind the shield arrival end segment, continue to excavate the core soil until the shield machine is dug out, and then dismantle the shield machine and transport it away from the construction site to complete the shield reception.

[0014] Furthermore, when the bottom of the shield starting pit is at or below the slightly weathered rock layer, the back wall and the portal sleeve base are directly constructed at the bottom of the pit; when the bottom of the shield starting pit is above the slightly weathered rock layer, the bottom plate is first constructed at the bottom of the pit, and then the back wall and the portal sleeve base are constructed on the bottom plate.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention sets a back wall, a portal sleeve base and a portal sleeve in the shield starting pit constructed by the slope method, and places the rear end of the portal sleeve against the slope of the shield starting pit. Plain concrete is filled in the portal sleeve to create shield starting conditions on the slope of the shield starting pit, thereby avoiding uneven force on the shield cutter head when the shield machine passes through the slope of the shield starting pit, and ensuring that the shield machine can start the shield safely and efficiently.

[0017] (2) The present invention retains the core soil in the arrival well of the shield machine constructed by the slope method, thereby ensuring the stability of the excavated slope and the core soil itself when the shield machine arrives, and ensuring that the shield machine can implement the shield reception safely and efficiently;

[0018] (3) The shield tunnel portal structure system and construction method constructed by the slope method of the present invention have a wide range of applications and are not limited to the size of the shield tunnel and the industry served. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a cross-sectional view of a shield shaft structure in the prior art;

[0021] Figure 2 The plan view of the shield launching shaft structure for the slope method construction;

[0022] Figure 3 This is the longitudinal section of the shield starting shaft constructed using the slope method;

[0023] Figure 4 This is the cross-sectional view of the shield tunnel portal constructed using the slope method;

[0024] Figure 5 This is the plan view of the shield arrival shaft structure constructed using the slope method;

[0025] Figure 6This is the longitudinal section of the shield tunneling shaft constructed using the slope method;

[0026] Figure 7 This is the cross-sectional view of the shield reaching the shaft portal during the slope method construction;

[0027] In the figure: 1. Retaining structure; 2. Main structure of shield shaft; 3. End wall of shield shaft portal; 4. Early ring beam of portal; 5. Shield tunnel; 6. Slope of foundation pit of shield starting shaft; 7. Bottom plate; 8. Back wall; 9. Portal sleeve base; 10. Portal sleeve; 11. Embedded parts; 12. Plain concrete; 13. Cutterhead; 14. Segment of shield starting end; 15. Later interface of shield starting shaft; 16. Slope of foundation pit of shield arrival shaft; 17. Core soil; 18. Segment of shield arrival end; 19. Shield machine; 20. Later interface of shield arrival shaft. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0029] Example 1

[0030] This embodiment provides a shield tunnel portal structure system constructed by the slope method, including a shield starting structure and a shield receiving structure. The shield starting structure includes a back wall 8, a tunnel portal sleeve base 9 and a tunnel portal sleeve 10. Figure 2-Figure 4 As shown, the shield starting pit is excavated to the bottom, and the back wall 8, the portal sleeve base 9 and the portal sleeve 10 are all arranged in the shield starting pit. The portal sleeve 10 is arranged on the portal sleeve base 9, and the front end of the portal sleeve 10 is pre-embedded with embedded parts 11 necessary for shield starting, and the rear end of the portal sleeve 10 is against the slope 6 of the shield starting pit; the portal sleeve 10 is filled with plain concrete 12, and the front end surface of the plain concrete 12 is parallel to the cutter head surface of the shield machine; the back wall 8 is arranged opposite to the portal sleeve base 9, and one side of the back wall 8 is arranged vertically, and the other side is against the slope 6 of the shield starting pit.

[0031] In this embodiment, a back wall 8, a portal sleeve base 9 and a portal sleeve 10 are set in the shield starting pit constructed by the slope method, and the rear end of the portal sleeve 10 is pressed against the shield starting pit slope 6, and plain concrete 12 is filled in the portal sleeve 10 to create shield starting conditions on the shield starting pit slope 6, thereby avoiding uneven force on the shield machine cutter head when the shield machine 19 passes through the shield starting pit slope 6, and ensuring that the shield machine can start the shield safely and efficiently.

[0032] Furthermore, a cutterhead compartment 13 is reserved between the front end of the plain concrete 12 and the front end of the portal sleeve 10. Optimally, the depth of this compartment 13 should ensure that when the shield cutterhead enters the compartment 13 and contacts the front end of the plain concrete 12, the rear end of the shield cutterhead and the portal water-stop rubber curtain are disengaged, leaving a gap between them. This ensures that the portal water-stop rubber curtain is not damaged by the shield cutterhead when excavation begins, effectively sealing the portal entrance. Plain concrete 12 can be C15 plain concrete.

[0033] In this embodiment, the rear end face of the portal sleeve 10 is consistent with the slope of the shield starting shaft foundation pit slope 6, and the rear end face of the portal sleeve 10 is fixed on the shield starting shaft foundation pit slope 6.

[0034] In this embodiment, whether to install the base plate 7 is determined based on the geological conditions at the starting tunnel portal of the shield tunnel constructed using the slope method. When the starting tunnel portal of the shield tunnel constructed using the slope method is located at or below the slightly weathered rock layer, the self-stabilizing nature of the slightly weathered rock layer bedrock can be utilized to eliminate the need for a base plate 7 at the pit bottom. The back wall 8 and the portal sleeve base 9 can be directly installed at the leveled pit bottom. When the starting tunnel portal of the shield tunnel constructed using the slope method is located above the slightly weathered rock layer, a base plate 7 can be installed at the pit bottom, and the portal sleeve base 9 and the portal sleeve 10 can be installed on the base plate 7.

[0035] like Figure 5-Figure 7 As shown, the shield receiving structure includes a core soil 17 located in the shield arrival shaft, and the core soil 17 completely covers the shield machine 19 to reach the preset position in the shield arrival shaft and is higher than a certain height. In this embodiment, one end of the core soil 17 covers the exit, and the other end extends along the excavation direction of the shield machine, and can completely cover the shield machine 19 when the shield machine 19 completely enters the shield arrival shaft, and the core soil 17 extends from the bottom of the pit to a certain height above the exit in the vertical direction, which can play a role in counterpressure. In this embodiment, by arranging the core soil 17 in the shield arrival shaft, it is possible to ensure the stability of the slope that has been excavated when the shield arrives and the stability of the core soil 17 itself, thereby ensuring that the shield machine can implement shield reception safely and efficiently.

[0036] Optimally, the core soil 17 is the soil that has not been excavated when the shield reaches the bottom of the well foundation pit. Figure 6-Figure 7As shown, in this embodiment, before the shield machine 19 arrives at the shield arrival well, the shield arrival well foundation pit is not excavated to the bottom, and the original soil from the pit bottom to a certain height above the exit is retained as the core soil 17. This not only reduces the workload of backfilling and back-pressure soil piling, reduces construction costs and saves construction time, but also the core soil 17 is the original soil, which is consistent with the density of the surrounding soil, effectively solves the problem of uneven force on the shield machine cutter head when the shield machine 19 exits the hole, and at the same time ensures the stability of the slope that has been excavated when the shield arrives.

[0037] Example 2

[0038] like Figure 2-Figure 7 As shown, this embodiment provides a construction method for a shield tunnel portal structure system using a slope method, specifically:

[0039] The construction method for shield starting is as follows: using the slope method to excavate the shield starting shaft foundation pit to the bottom of the pit, constructing the back wall 8, the portal sleeve base 9 and the portal sleeve 10, and pre-embedded parts 11 required for shield starting at the front end of the portal sleeve 10; before the shield starts, plain concrete 12 is filled in the portal sleeve 10, the front end surface of the plain concrete 12 is parallel to the shield machine cutter head surface, and a cutter head chamber 13 is reserved between the front end surface of the plain concrete 12 and the front end surface of the portal sleeve 10; after the shield machine 19 is hoisted into place, the portal water-stop rubber curtain is fixed to the front end of the portal sleeve 10 through the embedded parts 11, when the shield machine cutter head enters the cutter head chamber 13 and contacts with the front end surface of the plain concrete 12, the tail of the shield machine cutter head is disengaged from the portal water-stop rubber curtain, and a gap is reserved between the two, and then the shield machine 19 breaks the plain concrete 12 to complete the shield starting;

[0040] The construction method for shield reception is: use the slope method to excavate the shield arrival shaft, retain the core soil 17 before the shield machine 19 reaches the tunnel portal, and form a temporary secondary slope; wait until the shield machine 19 excavates until it pushes out the shield to reach the shaft foundation pit slope 16 and then stops, completes the grouting and consolidation behind the shield arrival end segment 18, and then continues to excavate the core soil 17 until the shield machine 19 is dug out, and then the shield machine 19 is dismantled and transported away from the construction site to complete the shield reception.

[0041] Furthermore, when the shield tunnel portal constructed by the slope method is at or below the slightly weathered rock layer, the back wall 8 and the tunnel portal sleeve base 9 are directly constructed on the leveled pit bottom; when the shield tunnel portal constructed by the slope method is above the slightly weathered rock layer, the bottom plate 7 is first constructed on the pit bottom, and then the back wall 8 and the tunnel portal sleeve base 9 are constructed on the bottom plate 7.

[0042] When the shield starting construction is completed, the shield starting well later interface 15 is constructed at the tunnel portal; when the shield receiving construction is completed, the shield arrival well later interface 20 is constructed at the tunnel portal; the shield starting well later interface 15 and the shield arrival well later interface 20 serve as the tunnel portal and the subsequent tunnel interface.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A construction method for a shield tunnel portal structure system using a slope method, characterized by: The shield tunnel portal structure system constructed by the slope method includes a shield starting structure and a shield receiving structure. The shield starting structure includes a back wall, a portal sleeve base and a portal sleeve. The portal sleeve is arranged on the portal sleeve base, the front end of the portal sleeve is pre-embedded with embedded parts, and the rear end abuts against the slope of the shield starting shaft foundation pit; the portal sleeve is filled with plain concrete, and the front end surface of the plain concrete is parallel to the cutter head surface of the shield machine; the back wall is arranged opposite to the portal sleeve base, and one side of the back wall is arranged vertically, and the other side abuts against the slope of the shield starting shaft foundation pit; a cutter head bin is reserved between the front end surface of the plain concrete and the front end surface of the portal sleeve; The construction method for shield starting is as follows: excavate the shield starting pit to the bottom of the pit using the slope method, construct the back wall, portal sleeve base and portal sleeve, and pre-embed the necessary embedded parts for shield starting at the front end of the portal sleeve; before the shield starts, fill the portal sleeve with plain concrete, the front end of the plain concrete is parallel to the shield machine cutterhead surface, and a cutterhead chamber is reserved between the front end of the plain concrete and the front end of the portal sleeve; after the shield machine is hoisted into place, the portal water-stop rubber curtain is fixed to the front end of the portal sleeve through the embedded parts; when the shield machine cutterhead enters the cutterhead chamber and contacts the front end of the plain concrete, the tail of the shield machine cutterhead and the portal water-stop rubber curtain are separated, and then the shield machine breaks the plain concrete to complete the shield starting; The construction method for receiving the shield machine is: use the slope method to excavate the shield arrival shaft, retain stable core soil before the shield machine reaches the tunnel portal, stop the shield machine after it excavates to the slope of the well foundation pit where it has pushed the shield machine out, complete the grouting and consolidation behind the end segment of the shield machine, continue to excavate the core soil until the shield machine is dug out, then dismantle the shield machine and transport it away from the construction site to complete the shield reception.

2. The method for constructing a shield tunnel portal structure system using the slope method as claimed in claim 1, characterized in that: When filling the portal sleeve with plain concrete, a cutterhead compartment is reserved between the front end surface of the plain concrete and the front end surface of the portal sleeve. When the shield machine cutterhead enters the cutterhead compartment and contacts the front end surface of the plain concrete, the tail of the shield machine cutterhead is out of contact with the portal water-stop rubber curtain.

3. The method for constructing a shield tunnel portal structure system using the slope method as claimed in claim 1, characterized in that: When the shield machine cutter head enters the cutter head chamber and contacts the front end surface of the plain concrete, the tail end of the shield machine cutter head is out of contact with the water-stop rubber curtain of the tunnel portal.

4. The method for constructing a shield tunnel portal structure system using the slope method as claimed in claim 1, characterized in that: The bottom surface of the shield starting shaft foundation pit is provided with a bottom plate, and the portal sleeve base and the portal sleeve are both arranged on the bottom plate.

5. The method for constructing a shield tunnel portal structure system using the slope method as claimed in claim 1, characterized in that: The shield receiving structure includes core soil located in the shield arrival shaft, and the core soil completely covers the shield machine and reaches a preset position in the shield arrival shaft and is higher than a certain height.

6. The method for constructing a shield tunnel portal structure system using the slope method as claimed in claim 5, characterized in that: The core soil is the soil that has not been excavated when the shield reaches the bottom of the well foundation pit.

Images