The construction technology of large-diameter shield with small turning radius and capable of preventing water leakage or collapse of the tunnel opening

Abstract

The present invention discloses a construction process for a large-diameter shield machine with a small turning radius and preventing water leakage or collapse at the tunnel entrance, which includes the following steps: S1, closing the movable groove; S2, filling the shield tail grease, when the shield machine turns, the welding point is disconnected; when the front end and the rear end of the shield machine pass through the tunnel entrance flush, the waterproof rubber curtain plate can seal against the outer periphery of the annular joint. The present invention not only ensures that the shield machine maintains a waterproof seal when passing through the tunnel entrance, but also the shield tail grease after disconnection can effectively promote the front end and the rear end of the shield machine to turn relative to each other, and at the same time, after surface treatment, no movement obstacles will be formed, and no damage to the waterproof rubber curtain plate will be caused. Therefore, water-stop failure is avoided, and the probability of water leakage and tunnel door collapse at the tunnel entrance is reduced, and it is more conducive to the implementation of small-radius turning of shield excavation.

Description

Technical Field

[0001] The invention belongs to the technical field of shield tunnel construction, and in particular relates to a construction process in which a large-diameter shield has a small turning radius and can prevent water leakage or collapse of a tunnel opening. Background Art

[0002] In recent years, with the continuous advancement of national development strategies and infrastructure construction, and the further improvement of high-speed railway networks, highway networks, and urban road network structures, shield tunnel technology has become an indispensable key technology in the construction of major transportation and other infrastructure in my country.

[0003] At present, in shield construction, in order to achieve the turning of the shield machine, the whole body is taken as the center, and the turning is implemented by offsetting the shield machine around the center line. The defect of this is a large turning radius. Therefore, a split shield machine is adopted, and an active articulation device and an articulated cylinder are set on the shield machine to implement relative rotation of the front and rear of the shield machine. Therefore, a rotating active groove is formed between the front and rear of the shield machine. In this way, although the turning radius can be reduced, at the beginning of the shield, after the active groove of the shield machine enters the tunnel portal, the water-stop steel ring at the tunnel portal cannot fit the shield machine casing at the active groove, resulting in failure of the water-stop. At the same time, water leakage occurs at the tunnel portal, and severe cases may cause the tunnel portal to collapse. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a new construction process with a large-diameter shield having a small turning radius and capable of preventing water leakage or collapse of the tunnel opening.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a construction process of a large-diameter shield with a small turning radius and capable of preventing water leakage or collapse of the tunnel opening, wherein the shield machine used comprises a hinged shield front end and a shield rear end and an oil cylinder, wherein an active groove is formed between the shield front end and the shield rear end, and under the extension and contraction of the oil cylinder, the shield front end rotates relative to the shield rear end, and the construction process comprises the following steps:

[0006] S1. Closure of active groove

[0007] A ring joint is used to fix the front end of the ring joint to the tail of the front end of the shield, and the rear end of the ring joint to the front end of the rear end of the shield by multiple welding points. The surface of the welding part is smoothed, and the thickness of the welding point is at least 1 / 3 to 2 / 3 of the thickness of the ring joint.

[0008] S2. Filling of shield tail grease

[0009] Filling the shield tail grease into the internal space formed by the annular joint and the movable groove;

[0010] When the front and rear ends of the shield machine pass through the tunnel portal flushly, the water-stop rubber curtain plate can seal against the outer periphery of the annular joint; when the oil cylinder pushes the front end of the shield machine to turn relative to the rear end of the shield machine, the force exerted on the welding point is greater than its own limit force, and the welding point is disconnected.

[0011] Preferably, the annular joint is an annular steel plate, and multiple welding points are evenly spaced around the circumference of the annular joint, which is not easy to deform, ensuring the water-stopping effect when entering the tunnel, and also convenient for turning with a small radius.

[0012] According to a specific implementation and preferred aspect of the present invention, when the shield machine turns, the welding point is disconnected, and it is assumed that the number of cylinders is X, the maximum thrust of the cylinder design is Tmax, the actual thrust reduction coefficient is K, and the total tension on multiple welding points when the shield machine turns is N; the number of spot welding points on the steel plate of the shield machine shell is Y, the circumference of the shield machine shell is C, the maximum tension borne by each welding point is Fmax, and the arc length formed between each two adjacent welding points is L,

[0013] X×Tmax×K=N Formula (1)

[0014] N / Fmax=Y Formula (2)

[0015] C / Y=L Formula (3)

[0016] In the above formula, X, Tmax, K, and C are all known parameters of the shield machine, K is 0.2~0.5, and Fmax is obtained through tensile test. Therefore, the required number of welds and the arc length formed between two adjacent welds can be obtained, which is convenient for construction.

[0017] It should be noted that the value of K is directly related to the formation strength and the curve radius. When the formation strength is high and the curve radius is small, a large value should be taken; when the formation strength is low and the curve radius is large, a small value should be taken; when the formation strength is high and the curve radius is large, or when the formation strength is low and the curve radius is small, an intermediate value should be taken.

[0018] Preferably, the front end of the annular joint is fully welded to the rear end of the front end of the shield, and the thickness formed at the weld is greater than or equal to the thickness of the annular steel plate, so as to avoid welding falling off and affecting the implementation of the steering assistance.

[0019] According to another specific implementation and preferred aspect of the present invention, the thickness of the annular steel plate is 2-5 mm. In this example, the steel plate is 3 mm thick. If the steel plate is too thin, it will be easily bent by the water-stop steel plate when passing through the tunnel gate, resulting in grooves, which will also make the tunnel gate water-stop ring ineffective; if the steel plate is too thick and the strength is greater, the resistance to the shield body will increase when turning.

[0020] A circular steel plate is formed by splicing multiple arc-shaped steel plates with the center of the front end of the shield as the center of the circle.

[0021] The outer diameter of the annular steel plate is less than or equal to the outer diameter of the front end of the shield and the rear end of the shield. In this way, the steel plate is prevented from scratching the water-stop rubber curtain plate when passing through the tunnel door without affecting the sealing.

[0022] When the front end of the shield and the rear end of the shield pass through the tunnel portal in a flush manner, the outer contours of the front end of the shield, the annular steel plate and the rear end of the shield are flush.

[0023] In addition, in S2, the shield tail grease is injected from the outer periphery of the annular joint or the side wall of the active groove. It is selected according to actual needs. At the same time, due to the large diameter of the shield machine, the shield tail grease can be injected at multiple points synchronously.

[0024] Preferably, the movable groove gradually decreases from the outside to the inside, and the formed internal space also gradually decreases from the outside to the inside, so as to ensure that the shield tail grease can play a better supporting effect and can effectively promote the turning when the welding point is disconnected.

[0025] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] The present invention not only ensures that the shield machine maintains a water-stop seal when passing through the tunnel entrance, but also the shield tail grease after disconnection can effectively push the front end and the rear end of the shield to make relative turns. At the same time, after surface treatment, no movement obstacles will be formed, and no damage will be caused to the water-stop rubber curtain plate. Therefore, water-stop failure is avoided, the probability of water leakage and tunnel entrance collapse is reduced, and at the same time, it is more conducive to the implementation of small-radius turns for shield excavation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the construction process principle of this embodiment;

[0028] Figure 2 It is a front view schematic diagram of a shield machine with a large-diameter shield casing groove sealing structure of this embodiment;

[0029] Figure 3 It is a schematic cross-sectional view of the structure of a shield machine with a large-diameter shield casing groove sealing structure of this embodiment;

[0030] Among them: 1. Front end of shield; 2. Rear end of shield; 3. Movable groove; 4. Ring joint; 4a. Arc steel plate; 5. Shield tail grease; 6. Water-stop rubber curtain plate; H1. Full weld; H2. Welding point. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0037] like Figure 1 As shown, the construction process of the large-diameter shield in this embodiment has a small turning radius and can prevent water leakage or collapse of the tunnel opening, which includes: S1, closing the movable groove; S2, filling the shield tail with grease.

[0038] Combination Figure 2 and Figure 3 As shown, the shield machine used in this example includes a hinged shield front end 1 and a shield rear end 2 and an oil cylinder, wherein a movable groove 3 is formed between the shield front end 1 and the shield rear end 2, and under the extension and retraction of the oil cylinder, the shield front end 1 rotates relative to the shield rear end 2.

[0039] In this example, the shield machine also includes an annular joint 4 arranged at the movable groove 3 and a shield tail grease 5 filled in the internal space formed by the annular joint 4 and the movable groove 3, wherein the front and rear ends of the annular joint 4 are respectively connected to the tail of the shield front end 1 and the front of the shield rear end 2, and during the relative movement of the shield front end 1 and the shield rear end 2, after the force exerted on the rear end of the annular joint 4 is greater than its own limit force, the annular joint 4 is disengaged from the shield rear end 2, and when the shield front end 1 and the shield rear end 2 pass through the tunnel entrance flush, the waterproof rubber curtain plate 6 of the tunnel entrance can seal against the outer periphery of the annular joint 4.

[0040] The annular joint 4 is an annular steel plate, which is formed by splicing multiple arc-shaped steel plates 4a with the center of the shield front end 1 as the center of the circle. This is convenient for assembly, and in order to prevent scratching of the waterproof rubber curtain plate 6, the spliced ​​weld needs to be surface polished.

[0041] In this example, the steel plate is 3mm thick. If the steel plate is too thin, it will be easily bent by the water-stop steel plate when passing through the tunnel gate, resulting in grooves, which will also make the tunnel gate water-stop ring fail; if the steel plate is too thick and the strength is greater, the resistance to the shield body will increase when turning.

[0042] The outer diameter of the annular steel plate is smaller than the outer diameter of the shield front end 1 and the shield rear end 2. In this way, the steel plate is prevented from scratching the water-stop rubber curtain plate 6 when passing through the tunnel door without affecting the sealing.

[0043] The annular joint 4 is fixed to the tail of the front end 1 of the shield by full welding from the front end, and is fixed to the front end of the rear end 2 of the shield by spot welding from the rear end, and the welding points H2 formed by multiple spot welding are distributed around the circumference of the annular steel plate at intervals. In this way, it is convenient to implement the force separation between the annular joint and the rear end of the shield.

[0044] In this example, after welding, the annular steel plate, the front end of the shield, and the rear end of the shield are flush. In this way, after being flush, not only the relative sliding effect is good, but also the water-stop rubber curtain plate will not be scratched when the steel plate passes through the tunnel door, ensuring the sealing.

[0045] At the same time, the full weld at the front end of the steel plate (full weld H1) should be polished into a smooth surface.

[0046] In addition, in this example, the layout of the solder joints is as follows:

[0047] The number of spot welding points H2 is the ratio of the actual tensile force on the spot welding points when the shield machine turns to the maximum tensile force borne by each spot welding point, and the number of welding points is an integer.

[0048] When the shield machine turns, the actual pulling force on the spot welding points is equal to the product of the number of cylinders, the maximum design thrust of the cylinders, and the actual thrust reduction coefficient. The number of cylinders, the maximum design thrust of the cylinders, and the actual thrust reduction coefficient are all known numbers.

[0049] The maximum tensile force that each spot weld can withstand can be obtained by experiment. In this way, the number of welds can be designed according to the needs to ensure that the spot welds can fall off when turning.

[0050] The arc lengths between each two adjacent spot welding points are equal, which is convenient for construction, and also facilitates the separation effect under stress and assists in turning.

[0051] The arc length between each two adjacent welding points is equal to the ratio of the circumference of the annular steel plate to the number of welding points. Therefore, the corresponding arc length can be obtained according to the number of welding points.

[0052] At the same time, force calculation: When the shield machine is turning, assuming that the number of extended cylinders is X, the maximum thrust of the cylinder design is T max , the actual thrust reduction coefficient is K, the total tension on multiple welding points when the shield machine turns is N; the number of spot welding points on the shield machine shell steel plate is Y, the circumference of the shield machine shell is C, the maximum tension borne by each welding point is Fmax, and the arc length formed between each two adjacent welding points is L.

[0053] X×T max ×K=N (Formula 1)

[0054] N / Fmax=Y (Formula 2)

[0055] C / Y=L (Formula 3)

[0056] In the above formula, X, T max , K, and C are all known parameters of the shield machine, where K is taken as 0.2~0.5, and Fmax can be obtained through tensile tests.

[0057] Specifically, two steel plates are connected by three-point spot welding, and the two steel plates are pulled against each other until the welding points are damaged, and 1 / 3 of the tensile force obtained in the test is taken as Fmax.

[0058] In addition, it should be noted that the value of K is directly related to the formation strength and the curve radius. When the formation strength is high and the curve radius is small, a large value should be taken; when the formation strength is low and the curve radius is large, a small value should be taken; when the formation strength is high and the curve radius is large, or when the formation strength is low and the curve radius is small, an intermediate value should be taken.

[0059] In summary, the construction process of this embodiment is as follows:

[0060] S1. Closure of active groove

[0061] An annular steel plate is used, and the front end of the annular steel plate is fixedly connected to the tail of the front end of the shield by full welding, and the rear end of the annular joint is fixedly connected to the front end of the rear end of the shield by multiple welding points, wherein the thickness of the full welding is equal to the thickness of the annular steel plate, and then the surface of the welding point (full welding and spot welding) is smoothed, and the thickness at the welding point is 1 / 3 of the thickness of the annular joint. At the same time, the number of welding points Y and the arc length L between two adjacent welding points are obtained by the above formula, so the movable groove can be closed according to the design requirements;

[0062] S2. Filling of shield tail grease

[0063] Fill the shield tail grease into the internal space formed by the annular joint and the movable groove, wherein the shield tail grease is injected from the outer periphery of the annular joint. At the same time, due to the large diameter of the shield machine, the shield tail grease can be injected at multiple points synchronously.

[0064] After completing the above process, when the front end and the rear end of the shield pass through the tunnel portal flush, the water-stop rubber curtain plate can seal against the outer periphery of the annular joint; when the oil cylinder pushes the front end of the shield to turn relative to the rear end of the shield, the force exerted on the weld point is greater than its own limit force, and the weld point is disconnected.

[0065] Therefore, this embodiment has the following advantages:

[0066] Filling the groove with a disconnectable annular joint that bears force during turning not only ensures that the shield machine maintains a watertight seal when passing through the tunnel opening, but also the shield tail grease after disconnection can effectively push the front and rear ends of the shield to turn relative to each other. At the same time, the surface treatment will not form movement obstacles, nor will it cause damage to the watertight rubber curtain plate. Therefore, watertight failure is avoided, the probability of water leakage and tunnel door collapse is reduced, and it is more conducive to the implementation of shield tunneling turning.

[0067] By reasonably selecting the K value and combining it with the Fmax test, the number and accurate position distribution of the weld points are obtained, so that the weld points are ensured to be damaged during the stress, so as to complete the turning at a smaller turning radius.

[0068] The thickness of the annular steel plate used in this application mainly forms an effective match with the movable groove shape and the shield tail grease filling. When passing through the tunnel gate, it is not easily bent by the water-stop steel plate to produce grooves, which will cause the tunnel gate water-stop ring to fail; when turning, it is also easy to break and will not increase the resistance of shield excavation.

[0069] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A construction process for a large-diameter shield with a small turning radius and capable of preventing water leakage or collapse of a tunnel opening, wherein the shield machine used comprises a hinged shield front end and a shield rear end and an oil cylinder, wherein an active groove is formed between the shield front end and the shield rear end, and under the extension and contraction of the oil cylinder, the shield front end rotates relative to the shield rear end, characterized in that: The construction process includes the following steps: S1. Closure of active groove A ring joint is used to fix the front end of the ring joint to the tail of the front end of the shield, and the rear end of the ring joint to the front end of the rear end of the shield by multiple welding points, wherein the surface of the welding part is smoothed, and the thickness of the welding point is at least 1 / 3 to 2 / 3 of the thickness of the ring joint; S2. Filling of shield tail grease Filling the shield tail grease into the internal space formed by the annular joint and the movable groove; When the front end and rear end of the shield pass through the tunnel portal flushly, the water-stop rubber curtain plate can seal against the outer periphery of the annular joint; when the oil cylinder pushes the front end of the shield to turn relative to the rear end of the shield, the force exerted on the welding point is greater than its own limit force, and the welding point is disconnected.

2. The construction process of the large-diameter shield machine with a small turning radius and capable of preventing water leakage or collapse of the tunnel opening according to claim 1 is characterized in that: The annular joint is an annular steel plate, and the multiple welding points are evenly spaced around the circumference of the annular joint.

3. The construction process of claim 2, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse at the tunnel opening, is characterized in that: When the shield machine turns, the welding points are disconnected. Assuming that the number of cylinders is X, the maximum thrust of the cylinder design is Tmax, the actual thrust reduction factor is K, and the total tension on multiple welding points when the shield machine turns is N; the number of spot welding points on the steel plate of the shield machine shell is Y, the circumference of the shield machine shell is C, the maximum tension on each welding point is Fmax, and the arc length formed between each two adjacent welding points is L. X×Tmax×K=N Formula (1) N / Fmax=Y Formula (2) C / Y=L Formula (3) In the above formula, X, Tmax, K, and C are all known parameters of the shield machine, among which K is taken as 0.2~0.5, and Fmax is obtained through tensile test.

4. The construction process of claim 2, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, is characterized in that: The front end of the annular joint is fully welded to the rear end of the front end of the shield, and the thickness formed at the welding point is greater than or equal to the thickness of the annular steel plate.

5. The construction process of claim 4, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, is characterized in that: The thickness of the annular steel plate is 2-5 mm.

6. The construction process of claim 5, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, characterized in that: The annular steel plate is formed by splicing a plurality of arc-shaped steel plates with the center of the front end of the shield as the center of the circle.

7. The construction process of claim 6, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, characterized in that: The outer diameter of the annular steel plate is less than or equal to the outer diameters of the front end of the shield and the rear end of the shield.

8. The construction process of claim 7, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, is characterized in that: When the front end of the shield and the rear end of the shield pass through the tunnel portal in a flush manner, the outer contours of the front end of the shield, the annular steel plate and the rear end of the shield are flush with each other.

9. The construction process of claim 1, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse of the tunnel opening, characterized in that: In S2, shield tail grease is injected from the outer periphery of the annular joint or the side wall of the movable groove.

10. The construction process of claim 1, wherein the large-diameter shield has a small turning radius and can prevent water leakage or collapse at the tunnel opening, characterized in that: The movable groove gradually becomes smaller from the outside to the inside, and the formed internal space also gradually becomes smaller from the outside to the inside.

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