A reinforcing support method for a slide-shear type of slope failure mode

Abstract

The application discloses a reinforcing support method for a slide-pile type slope failure mode, and a reinforcing support structure is composed of a steel rail pile structure (1), a prestressed anchor cable structure (2) and a frame beam structure (3) which are combined and connected into a whole; the steel rail pile structure (1) is composed of a row of steel rails which are vertically arranged in an upper slide-pile rock mass (4) of the slide-pile type slope failure structure and deeply penetrate into a stable bedrock in a bedding internal part; the prestressed anchor cable structure (2) is composed of a row of prestressed steel strands which are arranged in a lower rotating rock mass (5) of the slide-pile type slope failure structure and deeply penetrate into the stable bedrock in the bedding internal part; and the frame beam structure (3) is composed of two mutually parallel cross beams (3-1) and a row of vertical beams (3-2) which are in transition with the cross beams (3-1) and are mutually perpendicular to the cross beams (3-1). The application can play a role of "blocking upward and pulling downward" on the slide-pile type rock slope failure, meanwhile, the frame beam can effectively connect all the structures to form a complete reinforcing system, thereby guaranteeing the stability of the slide-pile type failure slope.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mine slope treatment, and particularly relates to a reinforcing and supporting method for a non-coal mine rock bedding slope sliding wedge failure. BACKGROUND

[0002] Mine slope failure and instability is a complex geological disaster process. Due to the complexity of the slope interior and the different rock materials that make up the slope, the slope failure has different modes, and the reinforcement and treatment methods are also different.

[0003] China is one of the countries with the most serious landslide disasters in the world. Landslide accidents have caused great threat to people's life and property safety.

[0004] Although there are various known rock slope failure modes, they can be classified into the following five types according to the failure mechanism: the first type is pure shear sliding failure; the second type is upper segment toppling and lower segment sliding failure; the third type is pure toppling failure; the fourth type is collapse failure; and the fifth type is collapse failure. The failure mode of each type depends on the spatial combination relationship of the rock mass structure of the rock slope, especially the discontinuous surface with relatively weak shear strength in the rock mass and the free surface of the slope. Due to the various rock mass structures in nature and various forms of slopes, other forms of slope failure modes may exist.

[0005] Open-pit mine slope problems directly affect the economic effect and safety of open-pit mining. In terms of the core causes of landslides, the first is the increase of sliding force, and the second is the decrease of anti-sliding force. At present, the slope treatment of most non-coal open-pit mines is basically the slope reinforcement after the formation of the slope free surface after excavation, such as the combined reinforcement method for slope landslide treatment with the patent number ZL201610437144.2, which uses a pile-anchor-beam combined structure to effectively improve the slope stability. However, this post-reinforcement method has a big defect. During the process of forming the slope free surface by excavation, the stress state of the slope rock mass, the slope surface sliding and the internal cracks have already been disturbed irreversibly due to the unloading deterioration mechanism, thereby affecting the stability of the entire slope, increasing the risk and treatment cost during the reinforcement process.

[0006] The "slip wedge failure type" is different from other typical slope failure modes as a special slope failure mode, which objectively exists in a few rock slopes in nature. The slip wedge failure is mainly divided into two parts, the upper part of which occurs bedding shear sliding, which is the main power of slope failure, and the lower part of which has a structural plane with an inclination greater than the slope angle and rotates around the slope toe under the extrusion of the upper rock mass. For typical slope failure modes, mature and reliable reinforcement methods have been developed, such as the advanced pre-stabilization reinforcement structure for the bedding pure shear sliding failure in the patent No. ZL 202221078323.9, but there is no targeted reinforcement measure for the slip wedge type of slope failure mode, so a reinforcement support structure suitable for the slip wedge failure of bedding slope is needed. SUMMARY

[0007] The purpose of the present application is to provide a reinforcement support method for the slip wedge type of slope failure mode in view of the lack of reinforcement measures for the slip wedge type of slope failure mode in the prior art.

[0008] In the present application, the slope slip wedge structure is composed of two parts of rock mass, wherein the upper rock mass occurs bedding shear failure, the lower end is plow-shaped, and is referred to as slip plow rock mass; the lower rock mass rotates under the sliding extrusion of the slip plow rock mass, and is referred to as rotating rock mass; the slope has a bedding weak structural plane, and at least one set of joints with the same direction as the slope and with an inclination greater than the slope angle, referred to as the extrusion wedge surface.

[0009] In order to achieve the above-mentioned purpose of the present application, the reinforcement support method for the slip wedge type of slope failure mode adopts the following technical scheme:

[0010] 1) The adopted reinforcement support structure is composed of a steel rail pile structure, a pre-stressed anchor cable structure and a frame beam structure which are combined into an integral structure; the steel rail pile structure is composed of a row of steel rails vertically arranged in the upper slip plow rock mass of the slip wedge slope failure structure and deeply into the internal stable bedrock of the bedding; the pre-stressed anchor cable structure is composed of a row of pre-stressed steel strands arranged in the lower rotating rock mass of the slip wedge slope failure structure and deeply into the internal stable bedrock of the bedding, and the pre-stressed anchor cable structure is arranged at an angle θ with the horizontal plane, and θ is in the range of 13-18°; the frame beam structure is composed of two mutually parallel cross beams and a row of vertical beams which are connected with the cross beams at both ends and perpendicular to the cross beams, and the spacing between adjacent vertical beams is 3000-4500mm, and the spacing between the two vertical beams can be adjusted according to the slope structure of the slip wedge failure.

[0011] 2) The calculation method of the pre-stress applied by the pre-stressed anchor cable structure is:

[0012] The calculation formula of the anti-sliding resistance provided by the pre-stressed anchor cable structure is:

[0013]

[0014] If the rock mass with sliding wedge structure is in limit equilibrium state, then:

[0015] F=F P

[0016] Further, the applied prestressed anchoring force is:

[0017]

[0018] In the formula:

[0019] F is the sliding force of the rock mass with sliding wedge structure, which can be calculated according to the position and length of the sliding surface;

[0020] F p is the anti-sliding resistance;

[0021] P is the applied prestressed anchoring force;

[0022] P n is the normal component of the anchoring force along the sliding surface;

[0023] P t is the directional component of the anchoring force along the sliding surface;

[0024] α is the sliding surface inclination angle, which is 20-60°;

[0025] θ is the included angle between the prestressed anchor structure (2) and the horizontal direction;

[0026] is the internal friction angle of the rock mass at the bottom corner shear outlet.

[0027] According to the above calculation results, the diameter and depth of the prestressed steel strand penetrating into the stable bedrock inside the bedding, and the spacing between two adjacent prestressed steel strands are determined.

[0028] Further, the top of the steel rail is anchored in the upper body of the frame beam structure, and the top of the prestressed anchor structure is anchored in the lower body of the frame beam structure.

[0029] As a preferred embodiment of the present application, the steel rail pile structure is filled with C20 fine stone concrete, and the grouting pressure is controlled between 0.6-0.8 MPa; the prestressed steel strand of the prestressed anchor structure is anchored by M30 cement mortar; the frame beam structure is poured with C30 concrete, and the cross beam and the vertical beam are both bundled by 4 steel bars.

[0030] ​The test research shows that the prestressed anchor cable structure is preferably arranged at an angle of 15 degrees with the horizontal plane, in which case the combined body formed by the rail pile structure, the prestressed anchor cable structure and the frame beam structure has the strongest reinforcing and supporting force and the most stable structure for the reinforcement and support of the rock slope wedge failure.

[0031] Compared with the prior art, the reinforcing and supporting method for the wedge type slope failure mode has the following beneficial effects after adopting the above technical scheme:

[0032] (1) The dynamic cause of the wedge failure is the bedding shear sliding of the upper plow rock mass, and the rail pile structure can effectively limit the bedding sliding of the upper plow rock mass and eliminate the source of the wedge failure.

[0033] (2) The active tensioning of the prestressed anchor cable structure enhances the normal stress of the rotating rock mass, increases the anti-sliding force of the lower rotating rock mass, effectively resists the extrusion from the upper plow, and reduces the rotation torque of the rotating rock mass, so that the rotating rock mass is not easy to rotate, and the rail pile structure and the prestressed anchor cable structure jointly play the role of “upper resistance and lower tensioning”, effectively stabilizing the slope stability.

[0034] (3) The frame beam structure connects the rail pile structure and the prestressed anchor cable structure frame beam, uniformly distributes the tensioning force of the anchor cable in the entire reinforcement range, effectively relieves the stress concentration near the borehole opening, reduces the displacement deformation and anchor cable prestress loss at the empty hole, enhances the integrity of the reinforcement system, and ensures the stability of the wedge type failure slope.

[0035] (4) The calculation method of the prestress applied by the prestressed anchor cable structure is provided, and according to the calculation results of the method, the diameter of the prestressed steel strand penetrating into the bedding internal stable bedrock, the depth of penetration, and the spacing between the two adjacent prestressed steel strands are determined, which not only ensures the safety of the slope, but also has lower material cost and construction cost. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a cross-sectional view of the reinforcing and supporting method for the wedge type slope failure mode.

[0037] Figure 2 It is a plan view of the frame beam structure designed by the application.

[0038] The reference signs are: 1-rail pile structure; 2-prestressed anchor cable structure; 3-frame beam structure; 3-1-cross beam; 3-2-vertical beam; 4-plow rock mass; 5-rotating rock mass; 6-bedding weak structural plane; 7-wedge surface. DETAILED DESCRIPTION

[0039] To better describe the present invention, the following detailed description, in conjunction with the accompanying drawings, provides a method for reinforcing and supporting slopes in a slip-and-split failure mode.

[0040] Depend on Figure 1 The cross-sectional schematic diagram of the present invention for a reinforcement and support method for a slip-cut type slope failure mode shows that the slope slip-cut structure consists of two rock masses. The upper rock mass undergoes bedding shear failure and the lower end is plow-shaped, referred to as the slip-cut rock mass 4. The lower rock mass rotates due to the sliding compression of the slip-cut rock mass 4, referred to as the rotating rock mass 5. The slope has a bedding weak structural surface 6, and at the same time there is at least one set of joints in the same direction as the slope and with a dip angle greater than the slope angle, referred to as the squeeze-cut surface 7.

[0041] Depend on Figure 1 The diagram shown is a cross-sectional view of a reinforcement and support method for a slip-type slope failure mode according to the present invention, and is combined with... Figure 2 As can be seen, the present invention provides a reinforcement support method for slope failure modes of slip-cutting. The reinforcement support structure is composed of a steel rail pile structure 1, a prestressed anchor cable structure 2, and a frame beam structure 3 connected into an integral structure. The steel rail pile structure 1 consists of a row of steel rails vertically arranged within the upper slip-cut rock mass 4 of the slip-cutting slope failure structure and extending into the stable bedrock within the bedding plane. The length of the steel rails should exceed the drilling depth and be no less than 30 cm. C20 fine aggregate concrete is used for grouting, and the grouting pressure is controlled between 0.6 and 0.8 MPa. The grouting speed should be kept moderate; too fast a speed will lead to hole collapse, while too slow a speed will damage the integrity of the pile body. Corrosion protection measures are taken for the steel pipes according to environmental conditions. Generally, 30 kg / m steel rails are used, and the top of the steel rails is anchored to the frame beam structure. In the upper part of structure 3, the prestressed anchor cable structure 2 consists of a row of prestressed steel strands arranged in the lower rotating rock mass 5 of the sliding slope failure structure and extending into the stable bedrock within the bedding plane. The anchorage length is 8m, and the anchoring body is M30 cement mortar. The prestressed anchor cable structure 2 is arranged at an angle of 15° to the horizontal plane, and the top of the prestressed anchor cable structure 2 is anchored in the lower part of the frame beam structure 3. The frame beam structure 3 consists of two parallel horizontal beams 3-1 and a row of vertical beams 3-2 that intersect with the horizontal beams 3-1 at both ends and are perpendicular to the horizontal beams 3-1. The spacing between adjacent vertical beams 3-2 is 3000-4500mm. The overall frame shape is rectangular, and it is cast with C30 concrete. Both the horizontal beams 3-1 and the vertical beams 3-2 use 4 strands. It is made of steel bars tied together.

[0042] The calculation method for the prestress applied to the prestressed anchor cable structure 2 described in this invention is as follows:

[0043] The formula for calculating the anti-slip resistance provided by prestressed anchor cable structure 2 is as follows:

[0044]

[0045] If the rock mass of slide wedge structure is in limit equilibrium state, then:

[0046] F=F P

[0047] Further, the applied prestressed anchoring force is obtained:

[0048]

[0049] In the formula:

[0050] F is the sliding force of the rock mass of slide wedge structure, which can be calculated according to the position and length of the structure surface;

[0051] F p is the anti-sliding resistance;

[0052] P is the applied prestressed anchoring force;

[0053] P n is the normal component of the anchoring force along the sliding surface;

[0054] P t is the directional component of the anchoring force along the sliding surface;

[0055] α is the sliding surface inclination angle, which is 20-60°;

[0056] θ is the included angle between the prestressed anchor structure (2) and the horizontal direction;

[0057] is the internal friction angle of the rock mass at the bottom corner shear outlet.

[0058] According to the above calculation results, the diameter of the prestressed steel strand penetrating into the stable bedrock inside the bedding, the depth of penetration, and the spacing between the two adjacent prestressed steel strands are determined.

[0059] The reinforcement and support method has been applied in the reinforcement and treatment project of the slide wedge damage of the rock slope of a certain iron mine. According to the special slide wedge damage mode of the rock slope, the upper slide wedge rock mass is supported by using the rail pile structure, the lower rotating rock mass is anchored and tensioned by using the prestressed anchor structure, and the frame beam structure is used to connect the rail pile and the prestressed anchor. The application results show that the reinforcement and support method can play the role of "upper support and lower tension" for the slide wedge damage of the rock slope, and the frame beam can effectively connect all structures to form a complete reinforcement system, thereby ensuring the stability of the slide wedge type damaged slope. Moreover, the application results show that the reinforcement and support method has a comprehensive construction cost which is 20%-60% lower than that of other reinforcement methods, and unexpected technical effects are achieved.

Claims

1. A method of reinforcing support for a wedge-type slope failure mode, characterized by The technical scheme is as follows: 1) the reinforcing support structure is composed of a steel rail pile structure (1), a prestressed anchor cable structure (2) and a frame beam structure (3); the steel rail pile structure (1) is composed of a row of steel rails vertically arranged in the upper ploughing rock mass (4) of the slide structure and penetrating into the stable bedrock inside the bedding; the prestressed anchor cable structure (2) is composed of a row of prestressed steel strands arranged in the lower rotating rock mass (5) of the slide structure and penetrating into the stable bedrock inside the bedding, and the prestressed anchor cable structure (2) is arranged at an angle θ with the horizontal plane, and the value of θ is in the range of 13-18°; the frame beam structure (3) is composed of two horizontal beams (3-1) and a row of vertical beams (3-2) at the two ends of the horizontal beams (3-1) and perpendicular to the horizontal beams (3-1), and the distance between adjacent vertical beams (3-2) is 3000-4500 mm; 2) the calculation method of the prestress applied by the prestressed anchor cable structure (2) is as follows: the calculation formula of the anti-sliding resistance provided by the prestressed anchor cable structure (2) is as follows: if the slide structure rock mass is in a limit equilibrium state, then: F = F P and the applied prestressed anchoring force is obtained as follows: in the formula: F is the sliding force of the slide structure rock mass, which can be calculated according to the position and length of the structure surface; F p For the anti-sliding resistance; P is the applied prestressed anchoring force; P n F is the normal component of the anchoring force along the slip plane; P t is the component of the anchoring force in the direction of the slip surface; α is the sliding surface inclination angle, and the value is 20-60°; θ is the angle between the prestressed anchor cable structure (2) and the horizontal direction; φb is the internal friction angle of the rock mass at the toe of the cut; according to the above calculation results, the diameter and depth of the prestressed steel strands penetrating into the stable bedrock inside the bedding and the distance between the two adjacent prestressed steel strands are determined.

2. A method of reinforcing support for a wedge-type slope failure mode as defined in claim 1, wherein: the top of the steel rail is anchored in the upper body of the frame beam structure (3).

3. A method of reinforcing support for a wedge-type slope failure mode as claimed in claim 1 or 2, characterized in that: the top of the prestressed anchor cable structure (2) is anchored in the lower body of the frame beam structure (3).

4. A method of reinforcing support for a wedge-type slope failure mode as defined in claim 3, wherein: the steel rail pile structure (1) is filled with C20 fine stone concrete, and the grouting pressure is controlled in the range of 0.6-0.8 MPa.

5. A method of reinforcing support for a wedge-type slope failure mode as defined in claim 4, wherein: the prestressed steel strands of the prestressed anchor cable structure (2) are anchored by M30 cement mortar.

6. A method of reinforcing support for a wedge-type slope failure mode as defined in claim 5, wherein: The frame beam structure (3) is poured with C30 concrete, and the cross beam (3-1) and the vertical beam (3-2) are both made of 4 steel bars. ​ 7. A method of reinforcing support for a wedge-type slope failure mode as defined in claim 6, wherein: the prestressed anchor cable structure (2) is arranged at an angle of 15° with the horizontal plane.

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