Strong weathered rock stratum grouting steel pipe foundation retaining wall construction method

Abstract

The invention relates to a construction method for a grouting steel pipe foundation retaining wall of a strongly weathered rock stratum, which comprises the following steps of: dividing a working surface at the top of the strongly weathered rock stratum, and leveling a soil body in the working surface; grouting pipes are provided, a plurality of grouting pipes are inserted in the working face at intervals, and grouting is conducted on the strongly weathered rock stratum through the grouting pipes; a foundation steel bar frame is bound on the working face, and a pouring formwork is arranged outside the foundation steel bar frame; concrete is poured into the pouring formwork to form the retaining wall; after the concrete is solidified, the formwork is dismantled, the soil body is backfilled on the side portion of the soil retaining plate, construction is convenient, and the using effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of mechanically constructed tunnels, in particular to a method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer. Background Art

[0002] With the vigorous development of the construction industry, the number of roads, bridges, dams and other projects has increased, the development and use of mountain areas has become more extensive, and the use of retaining walls has also been widely used. At present, the retaining wall mainly adopts the concrete base plate foundation. However, in the retaining wall projects constructed in rock formations with poor foundation bearing capacity such as strongly weathered rock formations, the traditional concrete base plate foundation often cannot meet the engineering requirements. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock stratum, wherein grouting is performed in the strongly weathered rock stratum to enhance the stability of the working surface, thereby meeting the construction requirements.

[0004] The technical solution to achieve the above purpose is a construction method of a strongly weathered rock stratum grouting steel pipe foundation retaining wall, comprising the following steps:

[0005] Dividing a working surface at the top of the strongly weathered rock layer and leveling the soil within the working surface;

[0006] Providing grouting pipes, inserting a plurality of the grouting pipes at intervals on the working surface, and injecting grout into the strongly weathered rock layer through the grouting pipes;

[0007] Binding a foundation steel bar frame on the working surface, and setting a casting template outside the foundation steel bar frame;

[0008] pouring concrete in the casting formwork to form a retaining wall;

[0009] After the concrete solidifies, the formwork is removed and soil is backfilled on the side of the retaining plate.

[0010] Furthermore, before the grouting pipe is used to grout the working surface, a pipe drill is provided, and a grouting hole is drilled on the working surface through the pipe drill, and an anchor pipe is arranged at the position of the grouting hole, and the grouting pipe is inserted into the grouting hole through the anchor pipe.

[0011] Further, the basic steel reinforcement frame includes: a bottom plate steel reinforcement frame laid on the surface of the working surface and a panel steel reinforcement frame vertically arranged on the top of the bottom plate steel reinforcement frame;

[0012] After the grouting pipe is grouting the working surface, the bottom plate steel bar frame is laid on the top of the working surface, and the bottom plate steel bar frame is welded and fixed to the side of the anchor pipe;

[0013] The panel reinforcement frame is tied on the top of the laid bottom plate reinforcement frame.

[0014] Furthermore, when setting the casting formwork, a first cushion block is provided, and the cushion block is set between the basic steel frame and the casting formwork, and the cushion block is fixed to the basic steel frame by binding.

[0015] Furthermore, before setting the casting formwork, a buttress steel frame is tied to the side of the foundation steel frame;

[0016] A connection template is arranged outside the buttress reinforcement frame, and the connection template is connected to the casting template;

[0017] Concrete is poured in the connection formwork to form a buttress.

[0018] Furthermore, when setting the connecting formwork, a second pad is provided, and a pad is set between the buttress reinforcement frame and the casting formwork, and the second pad is fixed to the buttress reinforcement frame by binding.

[0019] Furthermore, the retaining wall is formed with a plurality of expansion joints, and flexible materials are filled in the expansion joints.

[0020] Furthermore, a drainage ditch is formed on the top of the retaining wall.

[0021] Furthermore, before setting the casting formwork, a drain pipe is provided, and the drain pipe is tied to the foundation steel frame, and the drain pipe obliquely penetrates the foundation steel frame.

[0022] Furthermore, after pouring concrete in the pouring formwork, the concrete is cured.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Adding grouting pipes deep into the strongly weathered rock layer before the construction of the retaining wall foundation can effectively enhance the stability of the foundation, ensure the safety and smooth progress of the project, and increase the stability of the retaining wall by setting buttresses on the side of the retaining wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The overall structural diagram of a construction method for a grouting steel pipe foundation retaining wall in a strongly weathered rock formation.

[0026] Figure 2 This is a rendering of the effect of using a construction method for grouting steel pipe foundation retaining wall in strongly weathered rock strata.

[0027] Figure 3 This is a rendering of the arrangement of grouting holes for a construction method of grouting steel pipe foundation retaining wall in strongly weathered rock strata.

[0028] Figure 4 The overall structural diagram of the grouting hole of a construction method for a grouting steel pipe foundation retaining wall in a strongly weathered rock stratum is shown.

[0029] Figure 5 This is a top view of the grouting hole of a construction method for grouting steel pipe foundation retaining wall in strongly weathered rock strata.

[0030] Legend: 1. Retaining wall; 2. Expansion joint; 3. Buttress; 4. Grouting pipe; 41. Grouting hole; 42. Anchor pipe; 43. Bracket; 5. Strongly weathered rock layer; 6. Foundation steel frame; 7. Drainage ditch; 8. Drain pipe. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0032] See also Figure 1 A method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer comprises the following steps: dividing a working surface on the top of the strongly weathered rock layer 5 and leveling the soil in the working surface; providing a grouting pipe 4, inserting a plurality of the grouting pipes 4 at intervals on the working surface, and grouting the strongly weathered rock layer 5 through the grouting pipes 4; tying a foundation steel bar frame 6 on the working surface, and setting a casting template outside the foundation steel bar frame 6; casting concrete in the casting template to form a retaining wall 1; after the concrete solidifies, removing the template and backfilling the soil on the side of the retaining board.

[0033] In the present invention, a preferred implementation method is: divide the construction area according to the construction drawing. Before the formal construction, the underground obstacles within the construction range must be explored and the grouting pipe 4 must be inserted into the strongly weathered rock layer 5. The depth of the insertion is not less than 1m. When the grouting of the grouting pipe 4 encounters an obstacle, the position can be adjusted. The grouting must be carried out slowly, and the steady-pressure grouting should last for more than 2 minutes to ensure the fullness. The grouting amount is not less than 18kg / m; preferably, the two adjacent grouting pipes 4 are arranged at an overall interval of 1m. After the grouting is completed, the size of the foundation steel frame 6 is measured and laid out, and then the steel bars are tied; the tying of the foundation steel frame 6 should pay attention to the thickness of the protective layer of the steel bars. After the tying of the foundation steel frame 6 is completed, a casting template is set on the outside of the foundation steel frame 6. The concrete is transported to the site from the centralized mixing station by a tank truck, and the material is pumped into the casting template. The inserted vibrator is used for vibration, and over-vibration and leakage vibration are not allowed; after the concrete solidifies, the casting template is removed, and the removal period of the casting template should be based on the structure. The material characteristics, the position of the formwork and the strength of the concrete are determined; preferably, the casting formwork is a non-load-bearing formwork and should be removed only when the concrete strength can ensure that its surface and edges are not damaged. Generally, the side formwork can be removed only when the concrete compressive strength reaches 2.5MPa. The backfill soil should be filled only when the strength of the retaining wall 1 concrete reaches 80% of the design strength. No soil shall be piled above the design elevation of the high side of the retaining wall 1, and the remaining overload shall not be greater than 10KPa (the design overload of the road area shall not exceed 35KPa). The backfill is compacted by backfilling with crushed stone soil, and layered filling is carried out. The height of the layer is not more than 2m to ensure that the rolling capacity is solid and the positive solid coefficient is greater than 0.96; the content of mudstone, argillaceous siltstone, clay, and silty clay in the backfill soil is not more than 30%, and silt, cultivated soil, frozen soil, expansive soil and soil with an organic matter content greater than 5% shall not be used; before filling, the original slope surface must be cleared and trimmed into steps. The backfill can be filled only after the ground is roughened (the internal friction angle of the backfill is greater than 35° and the cohesion is greater than 10Kpa.

[0034] Furthermore, before the grouting pipe 4 is grouted to the working surface, a pipe drill is provided, and a grouting hole 41 is drilled on the working surface through the pipe drill, and an anchor pipe 42 is arranged at the position of the grouting hole 41, and the grouting pipe 4 is inserted into the grouting hole 41 through the anchor pipe 42. Preferably, after the pipe drill is drilled, the anchor pipe 42 is arranged at the top of the grouting hole 41 to facilitate the insertion of the grouting pipe 4 into the grouting hole 41.

[0035] Furthermore, the concrete used for grouting is 42.5MPa ordinary Portland cement, with a water-cement ratio of 0.45 to 0.5, and the grouting pressure is not less than 0.3MPa.

[0036] Furthermore, the grouting hole 41 is protected with an inverted triangle angle steel L30X4 (length 40) to prevent clogging. The grouting pipe 4 must be a hose, and a cloth strip must not be used as a grouting plug for sealing.

[0037] Furthermore, the anchor pipes 42 are in a plum blossom shape and are generally arranged at intervals of 1 m.

[0038] Further, the basic steel reinforcement frame 6 includes: a bottom plate steel reinforcement frame laid on the surface of the working surface and a panel steel reinforcement frame vertically arranged on the top of the bottom plate steel reinforcement frame;

[0039] After the grouting pipe 4 is grouting the working surface, the bottom plate steel bar frame is laid on the top of the working surface, and the bottom plate steel bar frame is welded and fixed to the side of the anchor pipe 42;

[0040] The panel reinforcement frame is tied on the top of the laid bottom plate reinforcement frame.

[0041] Furthermore, the steel bars of the bottom plate steel bar frame are locked in a crisscross pattern to the anchor pipe 42 and are fixedly connected by welding.

[0042] Furthermore, a bracket 43 is provided on the side of the anchor pipe 42. The bracket 43 locks the anchor pipe 42 in a crisscross shape, and the bottom of the bracket 43 is fixed to the bottom plate steel bar frame by welding.

[0043] Furthermore, when setting the casting formwork, a first pad is provided, and the pad is provided between the basic steel frame 6 and the casting formwork, and the pad is fixed to the basic steel frame 6 by binding. Preferably, the first pad is tightly tied to the basic steel frame 6, and the first pad should be made of fine stone concrete to ensure that the strength of the first pad is the same as the strength of the concrete structure; the installation of the first pad should ensure that the thickness of the protective layer of the steel bar meets the design requirements, and at the same time, it should be ensured that 4 per square meter, and the position of the pad should be checked frequently during the concrete construction process.

[0044] Furthermore, before setting the casting formwork, the buttress 3 steel frame is tied to the side of the foundation steel frame 6;

[0045] A connection template is arranged outside the buttress 3 reinforcement frame, and the connection template is connected to the casting template;

[0046] Concrete is poured in the connection formwork to form a buttress 3 , which supports the retaining wall 1 to ensure the stability of the retaining wall 1 .

[0047] Furthermore, when setting the connection template, a second pad is provided, and a pad is provided between the buttress 3 steel frame and the casting template, and the second pad is fixed to the buttress 3 steel frame by binding. Preferably, the second pad is tightly tied to the buttress 3 steel frame, and the second pad should be made of fine stone concrete to ensure that the strength of the second pad is the same as the strength of the concrete structure; the installation of the second pad should ensure that the thickness of the protective layer of the steel bar meets the design requirements, and at the same time, it should be ensured that 4 per square meter, and the position of the pad should be checked frequently during the concrete construction process.

[0048] Furthermore, the retaining wall 1 is formed with a plurality of expansion joints 2, and flexible materials are filled in the expansion joints 2. Preferably, the retaining wall 1 is provided with an expansion joint 2 every 15m, the expansion joint 2 has a width of 2cm, and the expansion joint 2 is filled with flexible materials such as free green hemp silk.

[0049] Furthermore, a drainage ditch 7 is formed on the top of the retaining wall 1. The drainage ditch 7 is used to enhance the drainage effect of the retaining wall 1 and prevent rainwater from damaging the retaining wall 1.

[0050] Furthermore, before setting the casting formwork, a drain pipe 8 is provided and tied to the foundation steel frame 6 , and the drain pipe 8 obliquely penetrates the foundation steel frame 6 .

[0051] Furthermore, the drainage holes are arranged in a staggered manner in a plum blossom shape with a certain distance between them. 75mm PVC pipes are used and the PVC pipes are wrapped with permeable geotextiles. The transverse slope of the drainage holes is 4%. During installation, the PVC pipes can be fixed by the steel bars in the foundation steel frame 6. For the drainage holes in the direction of the wall panel of the retaining wall 1, the PVC pipes must be in close contact with the front template, and the end faces of the PVC pipes must form corresponding inclined surfaces to ensure that there will be no leakage around the PVC pipes during the pouring of concrete, so that the panel is smooth and flat.

[0052] Furthermore, after pouring concrete in the casting formwork, the concrete is cured. Preferably, after the concrete is poured, a dedicated person is arranged to finish the concrete surface before the initial setting, and to perform a finishing and calendering treatment before the final setting of the concrete, and then the geotextile is covered for watering and moisture maintenance. When the climate is hot or windy, water can be applied after 2 to 3 hours to maintain a fully moist state. Under humid climate conditions, when the relative humidity of the air is greater than 60%, when ordinary cement is used, the moist curing time is not less than 7 days.

[0053] The following is an explanation of the use process of the strongly weathered rock stratum grouting steel pipe foundation retaining wall construction method of the present invention.

[0054] Divide the construction area according to the construction drawings. Before the formal construction, the underground obstacles within the construction range must be explored and the grouting pipe 4 must be inserted into the strongly weathered rock layer 5. The insertion depth is not less than 1m. When the grouting pipe 4 encounters an obstacle, the position can be adjusted. The grouting must be carried out slowly, and the steady-pressure grouting should last for more than 2 minutes to ensure the filling degree. The grouting amount is not less than 18kg / m; preferably, the two adjacent grouting pipes 4 are arranged with an overall interval of 1m. After the grouting is completed, the steel bars are tied after measuring and laying out the size of the foundation steel frame 6; the tying of the foundation steel frame 6 should pay attention to the thickness of the protective layer of the steel bars. After the tying of the foundation steel frame 6 is completed, a casting template is set on the outside of the foundation steel frame 6. The concrete is transported to the site from the centralized mixing station by a tank truck, and the material is pumped into the casting template. The inserted vibrator is used for vibration, and over-vibration and missed vibration are not allowed; after the concrete solidifies, the casting template is removed. The removal period of the casting template should be based on the characteristics of the structure and the location of the template. and the strength of concrete; preferably, the casting formwork is a non-load-bearing formwork and should be removed only when the concrete strength can ensure that its surface and edges are not damaged. Generally, the side formwork can be removed only when the concrete compressive strength reaches 2.5MPa. The backfill soil should be filled only when the strength of the retaining wall 1 concrete reaches 80% of the design strength. No soil shall be piled above the design elevation of the high side of the retaining wall 1, and the remaining overload shall not be greater than 10KPa (the design overload of the road area shall not exceed 35KPa). The backfill is compacted by backfilling with crushed stone soil, and layered filling is carried out. The height of the layer is not more than 2m to ensure that the rolling capacity is solid and the positive solid coefficient is greater than 0.96; the content of mudstone, argillaceous siltstone, clay, and silty clay in the backfill soil is not more than 30%, and silt, cultivated soil, frozen soil, expansive soil and soil with an organic matter content greater than 5% shall not be used; before filling, the original slope surface must be cleared and trimmed into steps. The backfill can be filled only after the ground is roughened (the internal friction angle of the backfill is greater than 35° and the cohesion is greater than 10Kpa.

[0055] The present invention is described in detail above in conjunction with the embodiments of the accompanying drawings. A person skilled in the art can make various variations of the present invention according to the above description. Therefore, certain details in the embodiments should not constitute a limitation of the present invention, and the scope of protection of the present invention shall be defined by the scope of the attached claims.

Claims

1. A method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock formation, characterized in that: The steps include: Dividing a working surface at the top of the strongly weathered rock layer and leveling the soil within the working surface; Providing grouting pipes, inserting a plurality of the grouting pipes at intervals on the working surface, and injecting grout into the strongly weathered rock layer through the grouting pipes; Binding a foundation steel bar frame on the working surface, and setting a casting template outside the foundation steel bar frame; pouring concrete in the casting formwork to form a retaining wall; After the concrete solidifies, the formwork is removed and soil is backfilled on the side of the retaining plate.

2. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1 is characterized by: Before the grouting pipe is grouting the working surface, a pipe drill is provided, and a grouting hole is drilled on the working surface through the pipe drill. An anchor pipe is arranged at the position of the grouting hole, and the grouting pipe is inserted into the grouting hole through the anchor pipe.

3. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 2 is characterized by: The basic steel reinforcement frame includes: a bottom plate steel reinforcement frame laid on the surface of the working surface and a panel steel reinforcement frame vertically arranged on the top of the bottom plate steel reinforcement frame; After the grouting pipe is grouting the working surface, the bottom plate steel bar frame is laid on the top of the working surface, and the bottom plate steel bar frame is welded and fixed to the side of the anchor pipe; The panel reinforcement frame is tied on the top of the laid bottom plate reinforcement frame.

4. The method for constructing a strongly weathered rock stratum grouting steel pipe foundation retaining wall according to claim 1, characterized in that: When setting the casting formwork, a first cushion block is provided, and the cushion block is arranged between the basic steel frame and the casting formwork, and the cushion block is fixed to the basic steel frame by binding.

5. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1 is characterized by: Before setting the casting formwork, tying the buttress steel frame to the side of the foundation steel frame; A connection template is arranged outside the buttress reinforcement frame, and the connection template is connected to the casting template; Concrete is poured in the connection formwork to form a buttress.

6. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 5 is characterized by: When setting the connecting formwork, a second pad is provided, and a pad is arranged between the buttress reinforcement frame and the casting formwork, and the second pad is fixed to the buttress reinforcement frame by binding.

7. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1 is characterized by: The retaining wall is formed with a plurality of expansion joints, and flexible materials are filled in the expansion joints.

8. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1 is characterized by: A drainage ditch is formed on the top of the retaining wall.

9. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1, characterized in that: Before setting the casting formwork, a drain pipe is provided and tied to the foundation steel frame, and the drain pipe obliquely penetrates the foundation steel frame.

10. The method for constructing a grouting steel pipe foundation retaining wall in a strongly weathered rock layer according to claim 1, characterized in that: After pouring concrete in the pouring formwork, the concrete is cured.

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