A kind of excavation slope pre-reinforcement pile wall support structure and method

Abstract

The present invention discloses a pre-reinforced pile wall support structure and method for excavated slopes, comprising a plurality of retaining piles arranged on the slope, a plurality of jet grouting piles arranged between two adjacent retaining piles along the soil arch line between the piles, wherein the jet grouting piles facing the rear side of the retaining piles are rear-pile jet grouting piles, and the remaining jet grouting piles are inter-pile jet grouting piles, wherein the rear-pile jet grouting piles have a vertical axis, and further comprising a retaining wall between the two retaining piles, wherein the front side of the retaining wall is a face slope, and the rear side of the retaining wall is adjacent to each inter-pile jet grouting pile. The purpose of the present invention is to provide a pre-reinforced pile wall support structure and method for excavated slopes, so as to solve the problem in the prior art that the retaining wall easily leads to partial failure of the pile wall support system, and to achieve the purpose of reducing the disturbance of the soil between the piles caused by the excavation in front of the piles and protecting the strength of the soil between the piles.

Description

Technical Field

[0001] The invention relates to the field of slope support, and in particular to an excavated slope pre-reinforced pile wall support structure and method. Background Art

[0002] When anti-slide piles are used to support the excavated slope, after the concrete of the pile reaches the design strength, the rock and soil in front of the pile can be excavated and the soil between the piles can be used for support. The soil support structure between the piles usually adopts retaining boards or retaining walls.

[0003] Retaining panels generally adopt a front hanging structure. The front hanging construction requires pre-embedded connectors in the pile body, and epoxy resin is generally used for anchoring. There are several problems in the anchoring and panel hanging process: First, the main reinforcement on the face side of the pile body is densely arranged, and the anchoring drilling will inevitably damage the main reinforcement, reducing the strength of the pile body structure; second, the protective layer on the face side of the main reinforcement is generally 5 to 7 cm, and the anchoring drilling is easy to damage the protective layer concrete; third, the positioning accuracy of the drilling and anchoring is difficult to guarantee, which easily causes the external hanging board to be uneven and the visual effect is poor.

[0004] As for the retaining structure using retaining walls, since the retaining walls can only be constructed after the soil in front of the piles is excavated to the designed elevation of the retaining wall base, when the soil strength between the piles is insufficient or encounters rainfall, it is very easy to cause the soil between the piles to become unstable and collapse, thereby causing partial failure of the pile wall support system. Summary of the invention

[0005] The purpose of the present invention is to provide a pre-reinforced pile wall support structure and method for excavated slopes, so as to solve the problem in the prior art that the retaining wall easily causes partial failure of the pile wall support system, thereby achieving the purpose of reducing the disturbance of the soil between piles caused by excavation before the piles and protecting the strength of the soil between the piles.

[0006] The present invention is achieved through the following technical solutions:

[0007] A pre-reinforced pile wall supporting structure for an excavated slope comprises a plurality of retaining piles arranged on the slope, a plurality of jet grouting piles are arranged between two adjacent retaining piles along the soil arch line between the piles, wherein the jet grouting piles facing the rear side of the retaining piles are rear-pile jet grouting piles, and the other jet grouting piles are inter-pile jet grouting piles, the axis of the rear-pile jet grouting piles is vertical, and the invention also comprises a retaining wall located between the two retaining piles, the front side of the retaining wall is a face slope, and the rear side of the retaining wall is adjacent to the inter-pile jet grouting piles.

[0008] In view of the problem that the retaining wall in the prior art easily leads to partial failure of the pile wall support system, the present invention proposes a pre-reinforced pile wall support structure for the excavated slope, wherein the retaining piles can be arranged on the slope according to the conventional design, and a number of jet grouting piles are arranged before two adjacent retaining piles. Among them, the jet grouting piles arranged next to the retaining piles on the rear side of the retaining piles are post-pile jet grouting piles, and the remaining jet grouting piles located between the two retaining piles are inter-pile jet grouting piles. A number of jet grouting piles are arranged along the inter-pile soil arch line, so that the post-pile jet grouting piles and inter-pile jet grouting piles between two adjacent retaining piles are connected into an arc structure, and the jet grouting piles between all retaining piles are distributed in a continuous M shape. The naming of the post-pile jet grouting piles and inter-pile jet grouting piles in this application is only for the convenience of distinguishing the jet grouting piles in different positions, and does not limit the structure or jet grouting process of the post-pile jet grouting piles and inter-pile jet grouting piles to be different. Jet-jet piles are made by using a drilling rig to place the jet-jet grouting pipe and nozzle at the designed elevation of the pile bottom. After the pre-prepared slurry is passed through a high-pressure generating device to make the liquid flow gain huge energy, it is ejected at high speed from the nozzle on the side of the grouting pipe to form a liquid flow with highly concentrated energy, which directly destroys the soil. During the injection process, the drill rod is rotated and lifted, so that the slurry and the soil are fully mixed and mixed, forming a columnar consolidation body of a certain diameter in the soil, thereby reinforcing the foundation. Although the jet-jet pile is a prior art, it has not been used in the field of anti-sliding pile support for excavated slopes. The present invention sets a retaining wall between two adjacent retaining piles. The front side of the retaining wall is a slope with a certain slope like the prior art, and the back side of the retaining wall is directly adjacent to the jet-jet piles between the piles, so that when the retaining wall is cast, there is no need to erect a back test formwork, and only the outer formwork needs to be cast in place, which ensures the smooth and neat surface of the facade, and has a good visual effect compared to the traditional front-mounted retaining board. The present invention is based on the theory of pile-soil interaction and the stress characteristics. The present invention uses a plurality of rotary jet piles distributed in an arc shape to pre-reinforce the soil behind and between the piles, which can reduce the pressure of the retaining wall soil when the pile hole is formed to a certain extent, and plays a temporary supporting and protective role for the soil between the piles after the soil in front of the pile is excavated in the cantilever section of the retaining pile, which minimizes the disturbance of the soil between the piles by the excavation in front of the pile, and protects the strength of the soil between the piles. In addition, since the retaining piles must be distributed vertically, the axis of the rotary jet pile behind the pile is also vertical, ensuring that the rotary jet pile behind the pile can be close to the retaining pile as a whole, ensuring that the rotary jet pile behind the pile has a stable and reliable reinforcement effect on the soil behind the pile.

[0009] Preferably, the jet grouting piles between two adjacent retaining piles are distributed along a curve consistent with the soil arch line on the horizontal plane, and the concave side of the curve faces the front side of the retaining piles. The front side of the retaining pile is the side of the retaining pile facing the bottom of the slope, and similarly, the back side of the retaining pile is the side facing the top of the slope. In this solution, the jet grouting piles are distributed in a curve between two adjacent retaining piles, and the concave side of the curve faces the front side of the retaining piles, which can better fit the stress conditions of the soil between the piles and provide better support and reinforcement effects after digging the soil in front of the piles.

[0010] Preferably, the axis of the jet grouting pile between piles is vertical or inclined: when the axis of the jet grouting pile between piles is vertical, the rear side of the retaining wall is also vertically distributed; when the axis of the jet grouting pile between piles is inclined, the rear side of the retaining wall is also inclined, and the degree of inclination of the rear side of the retaining wall is the same as that of the axis of the jet grouting pile between piles. That is, the jet grouting pile between piles can be set to be vertical or inclined. Inclined jet grouting piles between piles are more difficult to construct and require an inclined base to be prepared in advance before construction can be performed by jet grouting drilling. When inclined jet grouting piles between piles are selected, the volume of the required retaining wall is significantly reduced compared to vertical jet grouting piles between piles, so the concrete raw materials consumed in casting the retaining wall will be significantly reduced, which is beneficial to reducing the construction cost of the present invention.

[0011] Preferably, when the axis of the jet grouting pile between piles is inclined, the axis is parallel to the face slope. The axis of the jet grouting pile between piles is parallel to the face slope, and since the back side of the retaining wall is adjacent to the jet grouting pile between piles, the back side of the retaining wall must be parallel to the slope surface of its front side, so that the front and rear sides of the retaining wall are parallel and the structure is regular, reducing the risk of cement dehydration and stratification during the pouring process.

[0012] Preferably, it also includes a drainage hole penetrating the rotary jet pile.

[0013] A method for pre-reinforced pile wall support of excavated slopes comprises the following steps:

[0014] (a) Determine the position of retaining piles on the slope and carry out jet grouting construction along the soil arch line between two adjacent retaining piles;

[0015] (b) digging retaining piles;

[0016] (c) Excavation of soil in front of the cantilever section of the retaining pile;

[0017] (d) Set up the front formwork of the retaining wall and cast the retaining wall in place.

[0018] Preferably, the jet-jet piles between two adjacent retaining piles are distributed in a parabola, with the concave surface of the parabola facing the front side of the retaining piles.

[0019] Preferably, the rotary jet piles facing the rear side of the retaining piles are rear rotary jet piles, and the remaining rotary jet piles are inter-pile rotary jet piles, the axis of the rear rotary jet piles is vertical, and the axis of the inter-pile rotary jet piles is vertical or inclined; the casting area of ​​the retaining wall is the area surrounded by the retaining piles on both sides, the rotary jet piles between the retaining piles on both sides, and the front side formwork.

[0020] Preferably, the diameter of all jet grouting piles is d. When designing the retaining wall, the jet grouting pile body is equivalent to a part of the retaining wall thickness according to 0.8d. In engineering, there are certain requirements for the thickness of the retaining wall. For example, if the retaining wall thickness required for a certain project is D, if the present invention is adopted, the actual thickness of the retaining wall only needs to be set to (D-0.8d), and the front side template of the retaining wall can be set according to the thickness of (D-0.8d). Therefore, the setting of the jet grouting piles in the present invention can further assist the retaining wall in reinforcing the soil between the piles, and correspondingly reduce the construction cost of the retaining wall.

[0021] Preferably, the method further comprises step (e): after the strength of the retaining wall reaches the standard, drilling drainage holes penetrating the jet grouting piles.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. The present invention discloses a pre-reinforced pile wall support structure and method for excavated slopes. Based on the pile-soil interaction theory and stress characteristics, the soil behind and between the piles is pre-reinforced by a plurality of rotary jet piles distributed in an arc shape, which can reduce the pressure of the retaining wall soil when the pile hole is formed to a certain extent, and play a temporary supporting and protective role for the soil between the piles after the soil in front of the pile is excavated in the cantilever section of the retaining pile, thereby minimizing the disturbance of the soil between the piles by the excavation in front of the pile, and protecting the strength of the soil between the piles. In addition, since the retaining piles must be distributed vertically, the axis of the rotary jet pile behind the pile is also vertical, ensuring that the rotary jet pile behind the pile can be close to the retaining pile as a whole, ensuring that the rotary jet pile behind the pile has a stable and reliable reinforcement effect on the soil behind the pile.

[0024] 2. The present invention provides a pre-reinforced pile wall support structure and method for excavated slopes. When casting the retaining wall, there is no need to erect a tested formwork, and only the outer formwork needs to be cast in situ, thereby ensuring a smooth and neat exterior surface, and having a good visual effect compared to traditional front-mounted retaining panels.

[0025] 3. The present invention provides a pre-reinforced pile wall support structure and method for excavated slopes. The diameter of the jet grouting pile can be adjusted according to the site conditions. The jet grouting piles between the piles can be formed vertically or inclinedly as required. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0027] Figure 1 It is a schematic diagram of the placement of retaining plates in excavation retaining piles in the prior art;

[0028] Figure 2 It is a schematic diagram of the plan layout of a specific embodiment of the present invention;

[0029] Figure 3It is a schematic diagram of vertical arrangement of jet grouting piles between piles in a specific embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the inclined arrangement of the jet grouting piles between piles in a specific embodiment of the present invention.

[0031] Marks and corresponding parts names in the attached drawings:

[0032] 1- retaining piles, 2- jet grouting piles behind piles, 3- jet grouting piles between piles, 4- retaining wall, 5- face slope, 6- front hanging of retaining piles, 7- outer soil arch line, 8- inner soil arch line, 9- excavation datum surface. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0034] Embodiment 1:

[0035] like Figure 2 A pre-reinforced pile wall support structure for an excavated slope is shown, comprising a plurality of retaining piles 1 arranged on the slope, and is characterized in that a plurality of jet grouting piles are arranged between two adjacent retaining piles 1 along the soil arch line between the piles, wherein the jet grouting piles facing the rear side of the retaining pile 1 are the rear-pile jet grouting piles 2, and the remaining jet grouting piles are the inter-pile jet grouting piles 3, wherein the rear-pile jet grouting piles 2 have a vertical axis, and further comprising a retaining wall 4 located between the two retaining piles 1, wherein the front side of the retaining wall 4 is a face slope 5, and the rear side of the retaining wall 4 is adjacent to the inter-pile jet grouting piles 3.

[0036] Embodiment 2:

[0037] like Figures 2 to 4 The excavation slope pre-reinforcement pile wall support structure shown is based on Example 1, and the jet grouting piles between two adjacent retaining piles 1 are distributed in a parabola, and the concave surface of the parabola faces the front side of the retaining pile 1. The axis of the jet grouting pile 3 between the piles is vertical or inclined: when the axis of the jet grouting pile 3 between the piles is vertical, the rear side surface of the retaining wall 4 is also distributed vertically; when the axis of the jet grouting pile 3 between the piles is inclined, the rear side surface of the retaining wall 4 is also inclined, and the degree of inclination of the rear side surface of the retaining wall 4 is the same as that of the axis of the jet grouting pile 3 between the piles. When the axis of the jet grouting pile 3 between the piles is inclined, its axis is parallel to the face slope 5. It also includes a drainage hole that runs through the jet grouting pile.

[0038] The present embodiment consists of three parts: retaining piles, jet grouting piles, and retaining walls. The retaining piles are conventional rectangular cross-section piles, which are drilled manually. The jet grouting piles are distributed in a continuous M-shape on the plane with the back edge of the retaining piles, and the adjacent piles are distributed along the soil arch line between the piles, which is roughly parabolic. The jet grouting piles are made by using a drilling rig to place the jet grouting pipe and the nozzle drill at the designed elevation of the pile bottom. After the pre-prepared slurry is passed through a high-pressure generating device to give the liquid flow huge energy, it is ejected at high speed from the nozzle on the side of the grouting pipe to form a liquid flow with highly concentrated energy, which directly destroys the soil. During the spraying process, the drill rod is rotated and lifted at the same time, so that the slurry and the soil are fully mixed and mixed, forming a columnar consolidation body of a certain diameter in the soil, thereby reinforcing the foundation.

[0039] Jet-jet piles should be constructed with self-propelled crawler-type jet-jet machines. The jet-jet piles behind retaining piles are constructed with vertical jetting. The jet-jet piles between piles can be constructed with inclined or vertical jetting according to the cantilever height of the retaining piles. The inclination angle of the inclined jet-jet piles should be the same as the slope of the retaining wall.

[0040] The body of the jet grouting pile is a cement-soil structure, which can bear a certain amount of soil pressure. When designing and calculating the retaining wall, the body of the jet grouting pile can be regarded as a part of the thickness of the retaining wall at 0.8d.

[0041] The construction sequence of the pile wall system is: jet grouting pile construction → retaining pile construction → soil excavation in front of the cantilever section piles → construction of the wall between piles → drilling of drainage holes.

[0042] Embodiment 3:

[0043] (a) Determine the position of retaining piles 1 on the slope, and perform jet grouting construction along the soil arch line between two adjacent retaining piles 1;

[0044] (b) Digging retaining piles 1;

[0045] (c) Excavating the soil in front of the cantilever section of retaining pile 1;

[0046] (d) Set the front formwork of the retaining wall 4 and cast the retaining wall 4 in situ.

[0047] Compared with the prior art, this embodiment has the following beneficial effects:

[0048] (1) Based on the pile-soil interaction theory and stress characteristics, jet grouting piles are used to pre-reinforce the soil behind and between the piles. This can reduce the soil pressure on the retaining wall when the pile hole is drilled to a certain extent, provide temporary support and protection for the soil between the piles after the soil in front of the cantilever pile is excavated, and minimize the disturbance of the soil between the piles caused by the excavation in front of the piles and protect the strength of the soil between the piles.

[0049] (2) The jet grouting piles can be set at flexible angles. In addition to the vertical arrangement of the jet grouting piles behind the piles, the jet grouting piles between the piles can be set vertically or inclined as needed. The diameter of the jet grouting piles can be adjusted according to the site conditions.

[0050] (3) The retaining wall between piles is set up next to the jet grouting piles. No formwork is required on the back side, and only the outer formwork needs to be cast in place, which ensures that the facade is smooth and neat with good visual effects.

[0051] Embodiment 4:

[0052] A method for pre-reinforced pile wall support for excavated slopes, based on Example 3, the jet grouting piles between two adjacent retaining piles 1 are distributed in a parabola, and the concave surface of the parabola faces the front side of the retaining pile 1. The jet grouting piles facing the rear side of the retaining pile 1 are the rear jet grouting piles 2, and the remaining jet grouting piles are the inter-pile jet grouting piles 3, the axis of the rear jet grouting piles 2 is vertical, and the axis of the inter-pile jet grouting piles 3 is vertical or inclined; the casting area of ​​the retaining wall 4 is the area surrounded by the retaining piles 1 on both sides, the jet grouting piles between the retaining piles 1 on both sides, and the front side formwork. The diameter of all the jet grouting piles is d. When designing the retaining wall 4, the jet grouting pile body is equivalent to a part of the retaining wall thickness at 0.8d. It also includes step (e): after the strength of the retaining wall 4 reaches the standard, a drainage hole penetrating the jet grouting pile is drilled.

[0053] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of 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 method for pre-reinforcement of excavated slopes by pile wall support, characterized in that: A pre-reinforced pile wall support structure for an excavated slope, the support structure comprising a plurality of retaining piles (1) arranged on the slope, a plurality of jet grouting piles arranged between two adjacent retaining piles (1) along the soil arch line between the piles, wherein the jet grouting piles facing the rear side of the retaining piles (1) are rear jet grouting piles (2), and the remaining jet grouting piles are inter-pile jet grouting piles (3), the rear jet grouting piles (2) having a vertical axis, and further comprising a retaining wall (4) located between the two retaining piles (1), the front side of the retaining wall (4) being a face slope (5), and the rear side of the retaining wall (4) being adjacent to each inter-pile jet grouting pile (3); The axis of the jet grouting pile (3) between the piles is vertical or inclined: when the axis of the jet grouting pile (3) between the piles is vertical, the rear side of the retaining wall (4) is also vertically distributed; when the axis of the jet grouting pile (3) between the piles is inclined, the rear side of the retaining wall (4) is also inclined, and the degree of inclination of the rear side of the retaining wall (4) is the same as that of the axis of the jet grouting pile (3) between the piles; The jet-jet piles between two adjacent retaining piles (1) are distributed on a horizontal plane along a curve consistent with the soil arch line, with the concave surface of the curve facing the front side of the retaining pile (1); The support method comprises the following steps: (a) determining the position of retaining piles (1) on the slope, and performing jet grouting construction along the soil arch line between two adjacent retaining piles (1); (b) digging and installing retaining piles (1); (c) Excavation of soil in front of the cantilever section of retaining pile (1); (d) setting the front formwork of the retaining wall (4) and casting the retaining wall (4); The jet grouting piles facing the rear side of the retaining piles (1) are the rear jet grouting piles (2), and the remaining jet grouting piles are the inter-pile jet grouting piles (3); the axis of the rear jet grouting piles (2) is vertical, and the axis of the inter-pile jet grouting piles (3) is vertical or inclined; the casting area of ​​the retaining wall (4) is the area surrounded by the retaining piles (1) on both sides, the jet grouting piles between the retaining piles (1) on both sides, and the front template.

2. A method for pre-reinforcement of excavated slopes by pile wall support according to claim 1, characterized in that: When the axis of the inter-pile jet grouting pile (3) is inclined, the axis is parallel to the surface slope (5).

3. The method for pre-reinforcement of excavated slope by pile wall according to claim 1, characterized in that: It also includes a drainage hole that runs through the rotary jet pile.

4. The method for pre-reinforcement of excavated slope by pile wall according to claim 1, characterized in that: The diameter of all jet grouting piles is d. When designing the retaining wall (4), the jet grouting pile body is equivalent to a part of the retaining wall thickness at 0.8d.

5. The method for pre-reinforcement of excavated slope by pile wall according to claim 1, characterized in that: The method further comprises step (e): after the strength of the retaining wall (4) reaches the standard, drilling drainage holes penetrating the jet grouting piles.

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