Plateau gobi area PHC tubular pile guide hole pile sinking construction technology

Abstract

The invention discloses a guide hole pile sinking construction process for a PHC tubular pile in a gobi area of a plateau, relates to the technical field of PHC tubular pile construction, and aims to solve the problems that the construction of the PHC tubular pile is greatly challenged due to complex geological conditions, most of soil is loose gravel and the terrain fluctuation is relatively large in the gobi area of the plateau, and the construction progress is delayed due to the existence of a gravel layer, so that the construction cost is reduced. In order to solve the problem that more time and effort are needed to penetrate through the layers, the construction technology comprises the following steps that S1, preparation before construction is conducted, specifically, PHC pipe pile materials are prepared, surveying and setting-out are conducted through a total station, a theodolite or a level gauge, and a plane control network and an elevation control network of a project are built; the method has the advantages that it is guaranteed that various detection data such as the bearing capacity and the pulling resistance of a pile body meet the design requirements, and the pile is compact, resistant to hitting, high in penetrating capacity and high in adaptability to geological conditions with large terrain changes.

Description

Technical Field

[0001] The invention relates to the technical field of PHC pipe pile construction, and more specifically to a PHC pipe pile boring and pile sinking construction process in a plateau Gobi region. Background Art

[0002] In the late 1960s, my country began to develop pipe piles. After more than 50 years of use, prestressed concrete pipe piles have developed rapidly due to their reliable quality and reasonable cost. They are widely used in commercial housing, industrial plants, road traffic, ports and terminals and other fields. Especially in recent years, with the active participation of domestic scholars in theoretical research and practical application, the application of pipe piles in major and complex projects such as super high-rise buildings and large complexes has been actively promoted, which has expanded the application scope of pipe piles.

[0003] With the country's promotion of green environmental protection and the introduction of concepts such as industrial componentization, the application of pipe piles in engineering has been further promoted, which has saved a lot of concrete material resources, reduced concrete transportation, and reduced mud emissions, conforming to the principle of saving and reducing emissions and embarking on the path of sustainable development.

[0004] The geological conditions in the plateau Gobi region are complex, the soil is mostly loose gravel, and the terrain is undulating, which brings great challenges to the construction of PHC pipe piles. At the same time, the presence of gravel layers may also delay the construction progress because more time and effort are required to penetrate these layers. In view of this, we propose a PHC pipe pile boring and pile sinking construction process in the plateau Gobi region. Summary of the invention

[0005] The purpose of the present invention is to provide a PHC pipe pile boring and pile sinking construction process in the plateau Gobi area, aiming to solve the problem that the geological conditions in the plateau Gobi area are complex, the soil is mostly loose gravel, and the terrain is undulating, which brings great challenges to the construction of PHC pipe piles. At the same time, the presence of gravel layers may also lead to delays in construction progress because more time and effort are required to penetrate these layers.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a PHC pipe pile boring and pile sinking construction process in plateau Gobi areas, the construction process comprising the following steps:

[0007] S1: Preparation before construction: prepare PHC pile materials, use total station, theodolite or level to measure and lay out, and establish the plane control network and elevation control network of the project;

[0008] S2: Mechanical hole driving: For the situation of complex geology, multiple interlayers and deep bearing layer at the pile end, the hole driving method is adopted. The hole driving machine is used to reduce pressure and drive the hole. The drilling pressure at the bottom of the hole is controlled within 80% of the sum of the gravity of the drill rod, hammer head and pressure block to avoid inclined holes, bent holes and enlarged holes. The hole driving depth reaches the minimum effective pile length required by the design.

[0009] S3: Manual hole cleaning and hole forming: After the hole reaches the designed depth, the hole is manually cleaned to ensure that there is no residue in the hole. At the same time, the verticality of the hole-drilling machine is checked and adjusted to ensure that the verticality of the pile and the elevation of each unit pile meet the design requirements;

[0010] S4: Pile formation: Select the hammer type according to the pile length and ground conditions, adjust the verticality of the pile body after the pile is in place, gently insert the pile into the hole, and use the principle of "heavy hammer and light strike" to ensure that the static pressure penetration reaches the designed elevation. At the same time, record the soil penetration depth, final verticality, and original data of the hammer type;

[0011] S5: Grouting: In order to improve the pull-out resistance of the pile, grouting is carried out according to the pull-out resistance design requirements of the pile body. The grouting material is ordinary Portland cement with a strength grade of PO42.5. The water-cement ratio of the slurry is controlled within the range of 0.5-0.6. The grouting time and grouting amount must be strictly controlled;

[0012] S6: Backfill: After grouting is completed, backfilling is carried out to ensure that the quality and density of the backfill material meet the design requirements;

[0013] S7: Test and inspection: Test and inspect the piles after they are completed, including pile integrity inspection and bearing capacity inspection, to ensure that the quality of the piles meets the design requirements;

[0014] S8: Acceptance: According to relevant regulations and standards, the piles are inspected and accepted to ensure that the construction quality meets the design requirements.

[0015] Preferably, the above step S2 also includes the following steps:

[0016] S2.1: Select appropriate drill bit and drilling pressure according to formation characteristics to improve drilling quality and efficiency;

[0017] S2.2: During the drilling process, keep the drill rod and drill bit rotating continuously to avoid accidents such as drill sticking and drilling tools falling.

[0018] Preferably, the above step S3 also includes the following steps:

[0019] S3.1: During the hole cleaning process, use special tools to clean the residues on the hole wall and bottom to ensure that the hole is clean;

[0020] S3.2: When adjusting the verticality of the drill bit machine, use the machine's built-in balance instrument and two crossed theodolites or plumb bobs for auxiliary control.

[0021] Preferably, the above step S4 also includes the following steps:

[0022] S4.1: When inserting piles, use a ruler to adjust the verticality of the pile in two directions to ensure that the pile body is vertical;

[0023] S4.2: During the piling process, use a level to continuously monitor the pile to prevent the pile from tilting or shifting;

[0024] S4.3: During the piling process, the hammer stop time should be minimized. If it is necessary to stop the hammer, it should be stopped when the pile is sunk shallowly and the hammer stop time should be shortened as much as possible.

[0025] Preferably, the above step S5 also includes the following steps:

[0026] S5.1: Before grouting, check and debug the grouting equipment and grouting pipelines to ensure smooth grouting operation;

[0027] S5.2: During the grouting process, timely adjust the grouting parameters according to the changes in grouting pressure and grouting volume to ensure the quality and effect of grouting.

[0028] Preferably, the above step S6 also includes the following steps:

[0029] S6.1: Select appropriate backfill materials and ensure that the quality and density of the backfill materials meet the design requirements;

[0030] S6.2: During the backfilling process, adopt the layered backfilling and compaction method to ensure the uniformity and density of the backfill layer.

[0031] Preferably, the above step S7 also includes the following steps:

[0032] S7.1: Select appropriate test methods according to project needs, such as one or more of low-strain testing and high-strain testing;

[0033] S7.2: Analyze and evaluate the test results to ensure that the pile quality meets the design requirements.

[0034] Preferably, the above step S8 also includes the following steps:

[0035] S8.1: Carry out quality inspection and acceptance of piles after completion in accordance with relevant regulations and standards;

[0036] S8.2: Correct and handle any problems found during the acceptance process to ensure that the construction quality meets the design requirements.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. Aiming at different geological conditions in plateau Gobi areas, the present invention adopts a construction method of first drilling and then piling, that is, before piling, a drilling machine is used to drill holes and the holes are cleaned manually, and then a hydraulic pile hammer or a diesel hammer is used for pile driving construction, and finally the outer wall of the pile body is grouting and backfilled to ensure that the pile body bearing capacity and pull-out resistance test data meet the design requirements, the pile body is dense and durable, has strong penetration ability, and has strong adaptability to geological conditions with large terrain changes.

[0039] 2. The present invention has a short construction period, high efficiency, quick payback, a simple construction site, easy management, and can save construction costs.

[0040] 3. The PHC pipe piles of the present invention are easy to transport and hoist, the pile connection is rapid, the pile length is not limited, and free connection can be achieved.

[0041] 4. The optimization of grouting and backfilling operations in the present invention further improves the pull-out resistance and bearing capacity of the pipe piles, providing a strong guarantee for the long-term stable operation of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the construction process flow of the present invention. DETAILED DESCRIPTION

[0043] like Figure 1 As shown, the present invention relates to a PHC pipe pile boring and pile sinking construction process in a plateau Gobi region, and the construction process comprises the following steps:

[0044] S1: Preparation before construction: prepare PHC pile materials, use total station, theodolite or level to measure and lay out, and establish the plane control network and elevation control network of the project;

[0045] S2: Mechanical hole driving: For the situation of complex geology, multiple interlayers and deep bearing layer at the pile end, the hole driving method is adopted. The hole driving machine is used to reduce pressure and drive the hole. The drilling pressure at the bottom of the hole is controlled within 80% of the sum of the gravity of the drill rod, hammer head and pressure block to avoid inclined holes, bent holes and enlarged holes. The hole driving depth reaches the minimum effective pile length required by the design.

[0046] S3: Manual hole cleaning and hole forming: After the hole reaches the designed depth, the hole is manually cleaned to ensure that there is no residue in the hole. At the same time, the verticality of the hole-drilling machine is checked and adjusted to ensure that the verticality of the pile and the elevation of each unit pile meet the design requirements;

[0047] S4: Pile formation: Select the hammer type according to the pile length and ground conditions, adjust the verticality of the pile body after the pile is in place, gently insert the pile into the hole, and use the principle of "heavy hammer and light strike" to ensure that the static pressure penetration reaches the designed elevation. At the same time, record the soil penetration depth, final verticality, and original data of the hammer type;

[0048] S5: Grouting: In order to improve the pull-out resistance of the pile, grouting is carried out according to the pull-out resistance design requirements of the pile body. The grouting material is ordinary Portland cement with a strength grade of PO42.5. The water-cement ratio of the slurry is controlled within the range of 0.5-0.6. The grouting time and grouting amount must be strictly controlled;

[0049] S6: Backfill: After grouting is completed, backfilling is carried out to ensure that the quality and density of the backfill material meet the design requirements;

[0050] S7: Test and inspection: Test and inspect the piles after they are completed, including pile integrity inspection and bearing capacity inspection, to ensure that the quality of the piles meets the design requirements;

[0051] S8: Acceptance: According to relevant regulations and standards, the piles are inspected and accepted to ensure that the construction quality meets the design requirements;

[0052] The above step S2 also includes the following steps:

[0053] S2.1: Select appropriate drill bit and drilling pressure according to formation characteristics to improve drilling quality and efficiency;

[0054] S2.2: During the drilling process, keep the drill rod and drill bit rotating continuously to avoid accidents such as drill bit sticking and drill bit falling;

[0055] The above step S3 also includes the following steps:

[0056] S3.1: During the hole cleaning process, use special tools to clean the residues on the hole wall and bottom to ensure that the hole is clean;

[0057] S3.2: When adjusting the verticality of the drilling machine, use the machine's built-in balance instrument and two crossed theodolites or plumb bobs for auxiliary control;

[0058] The above step S4 also includes the following steps:

[0059] S4.1: When inserting piles, use a ruler to adjust the verticality of the pile in two directions to ensure that the pile body is vertical;

[0060] S4.2: During the piling process, use a level to continuously monitor the pile to prevent the pile from tilting or shifting;

[0061] S4.3: During the piling process, the hammer stop time should be minimized. If the hammer must be stopped, it should be stopped when the pile is sunk shallowly and the hammer stop time should be minimized;

[0062] The above step S5 also includes the following steps:

[0063] S5.1: Before grouting, check and debug the grouting equipment and grouting pipelines to ensure smooth grouting operation;

[0064] S5.2: During the grouting process, timely adjust the grouting parameters according to the changes in grouting pressure and grouting volume to ensure the grouting quality and effect;

[0065] The above step S6 also includes the following steps:

[0066] S6.1: Select appropriate backfill materials and ensure that the quality and density of the backfill materials meet the design requirements;

[0067] S6.2: During the backfilling process, adopt the layered backfilling and compaction method to ensure the uniformity and density of the backfill layer.

[0068] The above step S7 also includes the following steps:

[0069] S7.1: Select appropriate test methods according to project needs, such as one or more of low-strain testing and high-strain testing;

[0070] S7.2: Analyze and evaluate the test results to ensure that the pile quality meets the design requirements;

[0071] The above step S8 also includes the following steps:

[0072] S8.1: Carry out quality inspection and acceptance of piles after completion in accordance with relevant regulations and standards;

[0073] S8.2: Correct and handle any problems found during the acceptance process to ensure that the construction quality meets the design requirements;

[0074] Specifically, before the construction begins, first prepare the PHC pile materials and equipment to ensure that their quality meets the relevant standards and design requirements. Then, use the total station, theodolite or level measuring instrument to conduct precise measurement and layout to ensure the accuracy of the pile position. At the same time, establish the plane control network and elevation control network of the project to provide a reliable measurement benchmark for subsequent construction. The tools and equipment that need to be prepared are as follows:

[0075]

[0076] In view of the geological characteristics of the plateau Gobi region, the construction is carried out by the lead-hole piling method. First, according to the characteristics of the stratum, the appropriate drill bit and drilling pressure are selected to improve the quality and efficiency of the hole. The hole is decompressed by the lead-hole machine, and the bottom drilling pressure is strictly controlled within 80% of the sum of the gravity of the drill rod, hammer head, and pressure block to prevent the occurrence of inclined holes, bent holes, and enlarged holes. During the drilling process, the drill rod and drill bit are kept in continuous rotation to avoid the occurrence of drill jams and drill tool drops. The lead-hole depth must reach the minimum effective pile length required by the design to ensure the bearing capacity of the pile.

[0077] When the drilling hole reaches the designed depth, a manual hole cleaning operation is carried out, and special tools are used to clean the residues on the hole wall and bottom to ensure that the hole is clean and free of debris. At the same time, the verticality of the drilling machine is checked and adjusted, and the machine's built-in balance instrument and two crossed theodolites or plumb bobs are used for auxiliary control to ensure that the verticality of the pile and the elevation of each unit pile meet the design requirements;

[0078] Select the appropriate hammer type according to the pile length and stratum conditions. After the pile is in place, adjust the verticality of the pile body to ensure that the pile body is in close contact with the hole wall. Then, gently insert the pile into the hole and use the principle of "heavy hammer and light strike" to drive the pile. During the driving process, strictly control the hammer frequency and strength to ensure that the static pressure penetration reaches the designed elevation. At the same time, record the soil penetration depth, final verticality, and original data of the hammer type to provide a basis for subsequent quality inspections.

[0079] In order to improve the pull-out resistance of the pile, grouting is carried out according to the pull-out resistance design requirements of the pile body. Ordinary Portland cement is used as the grouting material, and the strength grade is PO42.5. The water-cement ratio of the slurry is controlled within the range of 0.5-0.6. Before grouting, the grouting equipment and grouting pipeline are inspected and debugged to ensure the smooth progress of the grouting operation. During the grouting process, the grouting parameters are adjusted in time according to the changes in the grouting pressure and grouting volume to ensure the quality and effect of the grouting. After the grouting is completed, the grouting holes are blocked;

[0080] After grouting is completed, backfilling is carried out. First, appropriate backfilling materials are selected to ensure that their quality and density meet the design requirements. During the backfilling process, layered backfilling and compaction methods are adopted to ensure the uniformity and density of the backfill layer. After each layer of backfilling is completed, compaction is carried out until the backfill height and density required by the design are reached;

[0081] Test the piles after they are built to verify whether their quality and bearing capacity meet the design requirements. Select appropriate test methods according to project needs, such as one or more of low-strain testing and high-strain testing. Analyze and evaluate the test results to promptly discover and deal with potential quality problems.

[0082] According to relevant regulations and standards, the quality of the piles after completion is inspected and accepted. During the acceptance process, the key indicators of the pile body verticality, elevation, and bearing capacity are checked one by one. Problems found during the acceptance process are rectified and dealt with to ensure that the construction quality meets the design requirements. Only after the acceptance is qualified can the subsequent construction and use be carried out.

[0083] Through the above specific implementation methods, the construction process of PHC pipe pile boring and pile sinking in plateau Gobi areas of the present invention is fully demonstrated. This process has significant advantages in plateau Gobi areas with complex geology, multiple interlayers, and deep bearing layers at the pile ends, and can ensure that the construction quality and bearing capacity of the pipe piles meet the design requirements. The following table shows the technical and economic comparison of PHC pipe piles with other pile types:

[0084]

[0085]

[0086] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A PHC pipe pile boring and pile sinking construction process in plateau Gobi areas, characterized in that: The construction process includes the following steps: S1: Preparation before construction: prepare PHC pile materials, use total station, theodolite or level to measure and lay out, and establish the plane control network and elevation control network of the project; S2: Mechanical hole driving: For the situation of complex geology, multiple interlayers and deep bearing layer at the pile end, the hole driving method is adopted. The hole driving machine is used to reduce pressure and drive the hole. The drilling pressure at the bottom of the hole is controlled within 80% of the sum of the gravity of the drill rod, hammer head and pressure block to avoid inclined holes, bent holes and enlarged holes. The hole driving depth reaches the minimum effective pile length required by the design. S3: Manual hole cleaning and hole forming: After the hole reaches the designed depth, the hole is manually cleaned to ensure that there is no residue in the hole. At the same time, the verticality of the hole-drilling machine is checked and adjusted to ensure that the verticality of the pile and the elevation of each unit pile meet the design requirements; S4: Pile formation: Select the hammer type according to the pile length and stratum conditions, adjust the verticality of the pile body after the pile is in place, gently insert the pile into the hole, and use the principle of "heavy hammer and light strike" to ensure that the static pressure penetration reaches the designed elevation. At the same time, record the soil penetration depth, final verticality, and original data of the hammer type; S5: Grouting: In order to improve the pull-out resistance of the pile, grouting is carried out according to the pull-out resistance design requirements of the pile body. The grouting material is ordinary Portland cement with a strength grade of PO42.

5. The water-cement ratio of the slurry is controlled within the range of 0.5-0.

6. The grouting time and grouting amount must be strictly controlled; S6: Backfill: After grouting is completed, backfilling is carried out to ensure that the quality and density of the backfill material meet the design requirements; S7: Test and inspection: Test and inspect the piles after they are completed, including pile integrity inspection and bearing capacity inspection, to ensure that the quality of the piles meets the design requirements; S8: Acceptance: According to relevant regulations and standards, the piles are inspected and accepted to ensure that the construction quality meets the design requirements.

2. A PHC pipe pile boring and pile sinking construction process in plateau Gobi area according to claim 1, characterized in that: The above step S2 also includes the following steps: S2.1: Select appropriate drill bit and drilling pressure according to formation characteristics to improve drilling quality and efficiency; S2.2: During the drilling process, keep the drill rod and drill bit rotating continuously to avoid accidents such as drill sticking and drilling tools falling.

3. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S3 also includes the following steps: S3.1: During the hole cleaning process, use special tools to clean the residues on the hole wall and bottom to ensure that the hole is clean; S3.2: When adjusting the verticality of the drill bit machine, use the machine's built-in balance instrument and two crossed theodolites or plumb bobs for auxiliary control.

4. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S4 also includes the following steps: S4.1: When inserting piles, use a ruler to adjust the verticality of the pile in two directions to ensure that the pile body is vertical; S4.2: During the piling process, use a level to continuously monitor the pile to prevent the pile from tilting or shifting; S4.3: During the piling process, the hammer stop time should be minimized. If it is necessary to stop the hammer, it should be stopped when the pile is sunk shallowly and the hammer stop time should be shortened as much as possible.

5. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S5 also includes the following steps: S5.1: Before grouting, check and debug the grouting equipment and grouting pipelines to ensure smooth grouting operation; S5.2: During the grouting process, timely adjust the grouting parameters according to the changes in grouting pressure and grouting volume to ensure the quality and effect of grouting.

6. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S6 also includes the following steps: S6.1: Select appropriate backfill materials and ensure that the quality and density of the backfill materials meet the design requirements; S6.2: During the backfilling process, adopt the layered backfilling and compaction method to ensure the uniformity and density of the backfill layer.

7. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S7 also includes the following steps: S7.1: Select appropriate test methods according to project needs, such as one or more of low-strain testing and high-strain testing; S7.2: Analyze and evaluate the test results to ensure that the pile quality meets the design requirements.

8. The construction process for PHC pipe pile boring and pile sinking in plateau Gobi area according to claim 1 is characterized in that: The above step S8 also includes the following steps: S8.1: Carry out quality inspection and acceptance of piles after completion in accordance with relevant regulations and standards; S8.2: Correct and handle any problems found during the acceptance process to ensure that the construction quality meets the design requirements.

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