Detection method of CFG pile composite foundation

Abstract

The detection method comprises the following steps that S1, a plurality of pile bodies are extracted, surface detection and quality detection of pile body forming are carried out, and the in-hole quality, the hole space and the pile body thickness of CFG piles are detected; s2, detecting the consolidation performance of the composite foundation; and S3, a static load and a dynamic load are applied to the CFG piles correspondingly, soil deformation and the consolidation effect around the CFG piles are observed, the consolidation effect of the soil around the piles is detected, and if the soil deformation and the consolidation effect of the soil around the piles are both met, the detection method of the CFG pile composite foundation meets the requirement. The construction quality of the engineering foundation can be improved, the quality of the CFG pile can be improved, the construction technology of the CFG pile can be optimized, and the engineering foundation construction method has the advantages of researching better economic, social and environmental benefits and strengthening the research on the composite foundation treatment technology. And a solid foundation is laid for obtaining good economic and social benefits for an engineering project which can be used for the CFG pile composite foundation in the future.

Description

Technical Field

[0001] The invention belongs to the technical field of CFG pile composite foundation, and in particular relates to a detection method for a CFG pile composite foundation. Background Art

[0002] During the foundation treatment construction process, it is necessary to divide the foundation treatment into different areas according to the foundation bearing capacity requirements of each functional area and the different settlement control standards, and then select the foundation treatment method suitable for the area, such as CFG pile composite foundation treatment. CFG pile is a low-strength concrete pile that can make full use of the bearing capacity of the soil between the piles and transfer the load to the deep foundation.

[0003] CFG piles are a commonly used construction technology for treating weak foundations with insufficient bearing capacity. They are widely used in engineering projects because of their simple operation and good reinforcement effect. Generally, after the construction is completed and its strength reaches stability, it is necessary to conduct single pile bearing capacity tests and composite foundation bearing capacity tests.

[0004] Composite foundations can be classified in many ways. According to the pile materials, they are divided into loose soil piles (made of loose materials such as sand and stones, which are gradually formed by the constraints of the surrounding soil layers. The bearing capacity depends on the lateral constraints of the soil layers around the piles and the internal friction angle of the pile materials), cement soil piles (cement soil mixing piles, rotary jet piles, etc.) and concrete piles (CFG piles, tree root piles, etc.). According to the stiffness of the pile body, they are divided into rigid piles (concrete piles), semi-rigid piles (cement soil piles) and flexible piles (loose soil piles); Specifically, it is divided according to the factors that affect the bearing capacity and settlement of the pile body due to the compression deformation of the pile body. According to the shape of the pile body material and the replacement effect of the pile body, it is divided into low bond strength piles (lime piles, etc.), medium bond strength piles (jet grouting piles, compacted cement piles, etc.), and high bond strength piles (CFG piles, etc.). In addition, it can also be classified according to the foundation type, the correlation between the strength of the reinforcement body and the original diagram, and the number of pile types.

[0005] The composite foundation treatment technology widely used in recent years is the screw pile composite foundation, which is a pile composite foundation composed of piles of different lengths. Under the action of load, the additional stress in the foundation will decrease with the increase of depth. Therefore, in order to more effectively utilize the bearing capacity of the pile in the composite foundation, piles of different lengths can be selected in the pile composite foundation to adapt to the characteristic that the additional stress decreases from top to bottom. The screw pile composite foundation has the advantages of high strength and small settlement, especially solving the problem of uneven settlement in the building, and can reduce the impact of seismic force on the structure. In addition, the materials used to make its screw piles are relatively conventional, which can save a lot of costs. Therefore, the screw pile composite foundation is widely used, especially in earthquake zones and soil layers that require artificial bearing capacity. Summary of the invention

[0006] In view of this, the present invention aims to propose a detection method for CFG pile composite foundation to solve at least one technical problem in the background technology.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows: The detection method of CFG pile composite foundation includes the following steps: S1: Select several pile bodies, conduct surface inspection and quality inspection of pile body molding, and inspect the in-hole quality, pore space, and pile body thickness of CFG piles; S2: Composite foundation consolidation performance test; S3: Apply static load and dynamic load to CFG piles respectively, observe soil deformation and consolidation effect around CFG piles, and test the consolidation effect of soil around piles. If all the conditions are met, the test method of CFG pile composite foundation meets the requirements.

[0008] Furthermore, the foundation inspection in step S1 is carried out 28 days after the completion of the construction, and CFG piles of no less than 10% of the total number of piles are extracted, and the CFG piles around and in the middle are evenly spaced, and the unconfined compressive strength of the pile body at 28 days old is not less than 10Mpa.

[0009] Furthermore, the surface inspection of the pile body in step S1 includes observing whether there are cracks on the appearance of the pile foundation and measuring the geometric dimensions and deformation of the impact; Quality inspection includes using a drilling machine to drill holes in the CFG piles, and then using an ultrasonic detector to measure the in-hole quality and pile thickness of the CFG piles.

[0010] Furthermore, in step S2, a consolidation test of the composite foundation is carried out using a consolidation instrument to test the consolidation, settlement and treatment effects; The number of tests in step S2 is 0.5% of the total number of piles, and the number of tests for each single project is not less than 3 points.

[0011] Further, in step S3, static load and dynamic load are applied to the CFG pile using a loading device; The load-bearing device includes a base, a support frame assembly, a first load-bearing assembly, and a second load-bearing assembly; The support frame assembly is arranged on the base, a plurality of first load-applying assemblies are arranged circumferentially below the support frame assembly, and a pressure plate is arranged at the bottom of the plurality of first load-applying assemblies; A plurality of second load-applying components are arranged around the supporting frame component.

[0012] Further, the support frame assembly includes side support rods and a top plate; A plurality of side support rods are evenly arranged on both sides of the base; The top plate is arranged above a plurality of side support rods.

[0013] Further, the first load-adding assembly includes a first hydraulic cylinder, a first push rod, and a first guide sleeve; The first hydraulic cylinder is installed at the bottom of the top plate, the end of the first hydraulic cylinder is connected to the first push rod, the first push rod can move along the first guide sleeve, and the first guide sleeve is installed on the first hydraulic cylinder; The end of the first push rod is connected to the pressure plate; The number of the first load-applying components is at least 6.

[0014] Further, the second load-adding assembly includes a second hydraulic cylinder, a second push rod, and a second guide sleeve; The second hydraulic cylinder is mounted on the base; The end of the second hydraulic cylinder is connected to the second push rod, the second guide sleeve is installed on the second hydraulic cylinder, and the second push rod can move along the second guide sleeve; The end of the second push rod is connected to the arc push rod; The number of the second load-applying components is four.

[0015] Furthermore, a plurality of evenly distributed insertion rods are provided on the base, and ends of the insertion rods extend underground.

[0016] Furthermore, the method of using the loading device comprises the following steps: A1: The first hydraulic cylinders of the first load-adding assembly push the first guide sleeve downward to the upper part of the CFG pile. The first hydraulic cylinders statically and continuously pressurize the CFG pile through the pressure plate to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A2 is performed. If not, it is unqualified. A2: The second hydraulic cylinder of one of the second load-adding assemblies pushes the second guide sleeve to move toward the CFG pile, and moves to one side of the CFG pile. The second hydraulic cylinder applies static and continuous pressure to the side of the CFG pile through the arc-shaped push rod. Several second load-adding assemblies perform the above operations in sequence, and observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements; A3: The first hydraulic cylinders of the first load-adding assembly push the first guide sleeve to reciprocate to the upper part of the CFG pile. The first hydraulic cylinders dynamically pressurize the CFG pile through the pressure plate to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A4 is performed. If not, it is unqualified. A4: The second hydraulic cylinder of one of the second load-adding assemblies pushes the CFG pile to reciprocate along the second guide sleeve and moves to one side of the CFG pile. The second hydraulic cylinder dynamically and continuously pressurizes the side of the CFG pile through the arc-shaped push rod. Several second load-adding assemblies perform the above operations in turn to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, it is unqualified if it does not meet the requirements.

[0017] Compared with the prior art, the detection method of the CFG pile composite foundation of the present invention has the following advantages: 1. This application can improve the quality of the foundation construction of the project, improve the quality of CFG piles, optimize the construction process of CFG piles, and conduct research to achieve better economic, social and environmental benefits. Research a greener and more economical CFG construction process under the premise of ensuring quality and efficiency, strengthen the research on composite foundation treatment technology, and lay a solid foundation for future projects that can use CFG pile composite foundations to achieve good economic and social benefits.

[0018] 2. The present application performs testing through the static and dynamic combination of the first load-adding component and the second load-adding component, and can be completed on one device. The test results are more accurate and labor is saved. The CFG pile can be tested in many aspects. The second load-adding component of the present application is arranged around the CFG pile, and the CFG pile is tested around each other, and the test results are accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 A schematic flow chart of a method for detecting a CFG pile composite foundation according to an embodiment of the present invention; Figure 2 is a schematic diagram of a loading device according to an embodiment of the present invention; Figure 3 It is a side schematic diagram of a loading device according to an embodiment of the present invention; Figure 4 Schematic diagram of the quality inspection standard described in the embodiment of the present invention.

[0020] Description of reference numerals: 1. Side support rod; 2. Top plate; 3. First hydraulic cylinder; 4. First push rod; 5. First guide sleeve; 6. Pressure plate; 7. Second hydraulic cylinder; 8. Second push rod; 9. Second guide sleeve; 10. Arc push rod; 11. Insert rod; 12. Base. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0025] Because the foundation bears all the loads from the foundation, it directly affects the safety of the main structure, so improving the construction quality of CFG piles is the top priority in construction. So we first analyze the reasons and find out the reasons for quality in five aspects: people, materials, machinery, methods, and environment. Among them, the main reason for the personnel arrangement may be the lack of personnel input, which leads to a long static load test and a long period of pile head cutting. The main reason for the long drilling pile cycle is the untimely supply of materials. The main reason for the machinery is that there are few equipment inputs and no construction equipment that matches the project site. It may also be that the unreasonable design of CFG piles causes easy blocking of pipes, resulting in slow concrete pouring or the pile length is too long, resulting in slow drilling, which will cause a long drilling pile cycle. Because this project is located in the city center, the construction is disturbed at night and other environmental factors lead to a long construction period. These are the reasons why the construction speed is affected. Therefore, the selection of reasonable sources of construction machinery and equipment, in-depth understanding of geological conditions, the use of reasonable construction technology, and strengthening of monitoring during the construction process can improve the quality and construction speed of CFG piles.

[0026] In the construction preparation stage, the selection of drilling rigs should fully consider the construction site conditions to avoid the drilling rig being too large and the site being too small, making it difficult to move up and down the foundation pit and when the borehole is shifted, thus delaying the construction period. Secondly, it is necessary to arrange the drilling route and the supporting equipment reasonably. Prevent pile leakage and reduce unnecessary pipeline laying, thereby saving costs. In terms of abandoned soil, the drilled soil should be removed from the foundation pit in time. If the remaining soil is not removed in time, it will not only affect the displacement of the drilling rig, but also affect the positioning accuracy of the borehole, causing the pile position to shift, and in serious cases, additional piles will be required, which will increase the cost.

[0027] During the construction process, drilling and pumping concrete are the most important links in the entire CFG pile construction. From the material point of view, the slump of concrete should be appropriate. If the slump is too small, it will block the pipe, affect the construction progress, waste concrete, and increase the cost; if the slump is too large, the pile will shrink too much after forming and the pile will collapse. If a soil layer with a high water content is encountered, it will also cause bottleneck piles, broken piles and other quality accidents. It is also necessary to pay attention to the speed of pumping concrete and strictly control the amount of concrete pressure to prevent excessive over-pouring of concrete and waste of materials.

[0028] The detection method of CFG pile composite foundation includes the following steps: S1: extracting a number of pile bodies, conducting surface detection and quality detection of pile body molding, and detecting the in-hole quality, pore space, and pile body thickness of the CFG pile; S2: testing the consolidation performance of the composite foundation; S3: applying static loads and dynamic loads to the CFG piles respectively, observing soil deformation and consolidation effects around the CFG piles, and testing the consolidation effects of the soil around the piles. If all of the above are met, the detection method of the CFG pile composite foundation meets the requirements.

[0029] The foundation inspection in step S1 is carried out 28 days after the completion of construction, and CFG piles of no less than 10% of the total number of piles are extracted, and CFG piles around and in the middle are evenly spaced, and the unconfined compressive strength of the pile body at 28 days is not less than 10Mpa. The surface inspection of the pile body in step S1 includes observing whether there are cracks on the appearance of the pile foundation, measuring the geometric dimensions and deformation of the impact; the quality inspection includes using a drilling machine to drill the CFG pile hole, and then using an ultrasonic detector to measure the in-hole quality and pile body thickness of the CFG pile.

[0030] In step S2, a consolidation test of the composite foundation is carried out using a consolidation instrument to test the consolidation, settlement and treatment effects; and the number of tests in step S2 is 0.5% of the total number of piles, and the number of tests for each single project is not less than 3 points.

[0031] In step S3, static load and dynamic load are applied to the CFG pile using a loading device; The load device includes a base 12, a support frame assembly, a first load-applying assembly, and a second load-applying assembly; the support frame assembly is arranged on the base 12, a plurality of first load-applying assemblies are arranged circumferentially below the support frame assembly, a plurality of first load-applying assemblies are provided with a pressure plate 6 at the bottom; a plurality of second load-applying assemblies are arranged around the support frame assembly. The support frame assembly includes a side support rod 1 and a top plate 2; a plurality of side support rods 1 are evenly arranged on both sides of the base 12; and the top plate 2 is arranged above a plurality of side support rods 1.

[0032] The first load-applying assembly includes a first hydraulic cylinder 3, a first push rod 4, and a first guide sleeve 5; the first hydraulic cylinder 3 is installed at the bottom of the top plate 2, the end of the first hydraulic cylinder 3 is connected to the first push rod 4, the first push rod 4 can move along the first guide sleeve 5, and the first guide sleeve 5 is installed on the first hydraulic cylinder 3; the end of the first push rod 4 is connected to the pressure plate 6; the number of the first load-applying assemblies is at least 6.

[0033] The second load-adding assembly includes a second hydraulic cylinder 7, a second push rod 8, and a second guide sleeve 9; the second hydraulic cylinder 7 is installed on the base 12; the end of the second hydraulic cylinder 7 is connected to the second push rod 8, the second guide sleeve 9 is installed on the second hydraulic cylinder 7, and the second push rod 8 can move along the second guide sleeve 9; the end of the second push rod 8 is connected to the arc push rod 10; the number of the second load-adding assemblies is 4.

[0034] A plurality of evenly distributed insertion rods 11 are provided on the base 12, and the ends of the insertion rods 11 extend underground.

[0035] The method of using the loading device comprises the following steps: A1: The first hydraulic cylinders 3 of the first load-adding assembly push the first guide sleeve 5 downward to the upper part of the CFG pile. The first hydraulic cylinders 3 statically and continuously pressurize the CFG pile through the pressure plate 6 to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A2 is performed. If not, it is unqualified. A2: The second hydraulic cylinder 7 of one of the second load-adding assemblies pushes along the second guide sleeve 9 to move toward the CFG pile, and moves to one side of the CFG pile. The second hydraulic cylinder 7 applies static and continuous pressure to the side of the CFG pile through the arc-shaped push rod 10. Several second load-adding assemblies perform the above operations in sequence, and observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements; A3: The first hydraulic cylinders 3 of the first load-adding assembly push the first guide sleeve 5 to reciprocate to the upper part of the CFG pile. The first hydraulic cylinders 3 dynamically pressurize the CFG pile through the pressure plate 6 to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A4 is performed. If not, it is unqualified. A4: The second hydraulic cylinder 7 of one of the second load-adding assemblies pushes the CFG pile to reciprocate along the second guide sleeve 9 and moves to one side of the CFG pile. The second hydraulic cylinder 7 dynamically and continuously pressurizes the side of the CFG pile through the arc push rod 10. Several second load-adding assemblies perform the above operations in turn to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, it is unqualified if it does not meet the requirements.

[0036] Quality inspection standards such as Figure 4 As shown, the present application performs testing through the static and dynamic combination of the first load-adding component and the second loading component, and can be completed on one device. The test results are more accurate and labor is saved. The CFG pile can be tested in many aspects. The second loading component of the present application is arranged around the CFG pile, and the surrounding areas of the CFG pile are tested respectively, and the test results are accurate.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The detection method of CFG pile composite foundation is characterized by: The steps include: S1: Select several pile bodies, conduct surface inspection and quality inspection of pile body molding, and inspect the in-hole quality, pore space, and pile body thickness of CFG piles; S2: Composite foundation consolidation performance test; S3: Apply static load and dynamic load to CFG piles respectively, observe soil deformation and consolidation effect around CFG piles, and test the consolidation effect of soil around piles. If all the conditions are met, the test method of CFG pile composite foundation meets the requirements.

2. The detection method of CFG pile composite foundation according to claim 1, characterized in that: The foundation inspection in step S1 is carried out 28 days after the completion of construction. No less than 10% of the total number of CFG piles are selected, and the CFG piles around and in the middle are evenly spaced. The unconfined compressive strength of the pile body at 28 days old is not less than 10Mpa.

3. The detection method of CFG pile composite foundation according to claim 1, characterized in that: The surface inspection of the pile body in step S1 includes observing whether there are cracks on the appearance of the pile foundation and measuring the geometric dimensions and deformation of the impact; Quality inspection includes using a drilling machine to drill holes in the CFG piles, and then using an ultrasonic detector to measure the in-hole quality and pile thickness of the CFG piles.

4. The detection method of CFG pile composite foundation according to claim 1, characterized in that: In step S2, a consolidation test of the composite foundation is carried out using a consolidation instrument to test the consolidation, settlement and treatment effects; The number of tests in step S2 is 0.5% of the total number of piles, and the number of tests for each single project is not less than 3 points.

5. The detection method of CFG pile composite foundation according to claim 1, characterized in that: In step S3, static load and dynamic load are applied to the CFG pile using a loading device; The load-bearing device includes a base, a support frame assembly, a first load-bearing assembly, and a second load-bearing assembly; The support frame assembly is arranged on the base, a plurality of first load-applying assemblies are arranged circumferentially below the support frame assembly, and a pressure plate is arranged at the bottom of the plurality of first load-applying assemblies; A plurality of second load-applying components are arranged around the supporting frame component.

6. The detection method of CFG pile composite foundation according to claim 5, characterized in that: The support frame assembly includes side support rods and a top plate; A plurality of side support rods are evenly arranged on both sides of the base; The top plate is arranged above a plurality of side support rods.

7. The detection method of CFG pile composite foundation according to claim 6, characterized in that: The first load-adding assembly includes a first hydraulic cylinder, a first push rod, and a first guide sleeve; The first hydraulic cylinder is installed at the bottom of the top plate, the end of the first hydraulic cylinder is connected to the first push rod, the first push rod can move along the first guide sleeve, and the first guide sleeve is installed on the first hydraulic cylinder; The end of the first push rod is connected to the pressure plate; The number of the first load-applying components is at least 6.

8. The detection method of CFG pile composite foundation according to claim 6, characterized in that: The second load-adding assembly includes a second hydraulic cylinder, a second push rod, and a second guide sleeve; The second hydraulic cylinder is mounted on the base; The end of the second hydraulic cylinder is connected to the second push rod, the second guide sleeve is installed on the second hydraulic cylinder, and the second push rod can move along the second guide sleeve; The end of the second push rod is connected to the arc push rod; The number of the second load-applying components is four.

9. The detection method of CFG pile composite foundation according to claim 6, characterized in that: A plurality of evenly distributed insertion rods are arranged on the base, and the ends of the insertion rods extend underground.

10. The detection method of CFG pile composite foundation according to claim 8, characterized in that: The method of using the loading device comprises the following steps: A1: The first hydraulic cylinders of the first load-adding assembly push the first guide sleeve downward to the upper part of the CFG pile. The first hydraulic cylinders statically and continuously pressurize the CFG pile through the pressure plate to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A2 is performed. If not, it is unqualified. A2: The second hydraulic cylinder of one of the second load-adding assemblies pushes the second guide sleeve to move toward the CFG pile, and moves to one side of the CFG pile. The second hydraulic cylinder applies static and continuous pressure to the side of the CFG pile through the arc-shaped push rod. Several second load-adding assemblies perform the above operations in sequence, and observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements; A3: The first hydraulic cylinders of the first load-adding assembly push the first guide sleeve to reciprocate to the upper part of the CFG pile. The first hydraulic cylinders dynamically pressurize the CFG pile through the pressure plate to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, step A4 is performed. If not, it is unqualified. A4: The second hydraulic cylinder of one of the second load-adding assemblies pushes the CFG pile to reciprocate along the second guide sleeve and moves to one side of the CFG pile. The second hydraulic cylinder dynamically and continuously pressurizes the side of the CFG pile through the arc-shaped push rod. Several second load-adding assemblies perform the above operations in turn to observe the soil deformation and the consolidation effect around the CFG pile. The consolidation effect of the soil around the pile is tested. If the deformation meets the requirements, it is unqualified if it does not meet the requirements.

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