Pile sinking method of prefabricated pipe pile in rock

Abstract

The invention discloses a pile sinking method of a prefabricated tubular pile in rock, which comprises the following steps of: (1) surveying and setting out at a construction site, and determining a guide hole position; (2) adopting a high-power rotary drilling rig as pile foundation guide hole equipment, and performing guide hole grouting; (4) when the distance between the pile top of the first section of the prefabricated pipe pile and the ground is 0.5-1.0 m, hoisting a second section of the prefabricated pipe pile, performing pile splicing operation, continuing pile sinking, and after the distance between the pile top of the first section of the prefabricated pipe pile and the ground is 0.5-1.0 m, hoisting the second section of the prefabricated pipe pile and the ground is 0.5-1.0 m, hoisting the second section of the prefabricated pipe pile; and (5) pile sinking operation of other sections of prefabricated pipe piles is carried out according to the step (4) until the piles are formed. The method is safe, reliable and easy to construct, overcomes the defects of a traditional pile sinking construction method, is more economical and effective compared with the traditional pile sinking construction method, and can be widely popularized in actual construction.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pile construction, in particular to a method for sinking prefabricated pipe piles in rocks. Background Art

[0002] Prefabricated pipe piles have the advantages of high pile bearing capacity, good bending resistance, reliable pile quality, short construction period, and good economic benefits. They have reasonable product structure, complete varieties and specifications, and a wide range of design options. They are now widely used in pile foundation construction. In construction, static pressure method and hammer method are usually used. However, when there are hard rock layers in the stratum, it is often difficult to sink the piles. Once forced construction is carried out, the pile body will be damaged, and the pile top elevation will not meet the design requirements, which will not only waste materials but also have adverse effects on the construction of the next process. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a method for sinking prefabricated pipe piles in rocks, which can specifically adopt the following technical solutions: The method for sinking prefabricated pipe piles in rocks of the present invention is suitable for construction of rock formations with a deformation model less than 20 MPa, and comprises the following steps: The first step is to measure and lay out the lines at the construction site to determine the location of the lead hole; The second step is to use a high-power rotary drilling rig as the pile foundation drilling equipment to carry out drilling and grouting; The third step is to use a guide rod diesel pile hammer to lift the first section of prefabricated pipe pile into place. After checking and adjusting the pile position, the pile end is put into the soil and initially pressurized. At the same time, the verticality of the pile body is checked and corrected, and then the pile sinking operation is officially started. During this process, the verticality of the pile body is always observed and corrected; Step 4: When the top of the first section of prefabricated pipe pile is 0.5-1.0m away from the ground, lift the second section of prefabricated pipe pile to connect the piles, and then continue to sink the piles, and keep a record of the pressure value during this process; The fifth step is to carry out the pile sinking operation of other segments of prefabricated pipe piles according to step four until the piles are completed.

[0004] Preferably, after the last section of prefabricated pipe pile is driven, the guide rod type diesel pile hammer is used for re-pressing at least three times, the final re-pressing settlement is controlled within 20 mm, and a detailed and accurate record is made of the termination pile driving force.

[0005] Preferably, a guide frame is provided on the pile frame below the guide rod type diesel pile hammer.

[0006] Preferably, a pile head is provided at the head of the first section of prefabricated pipe pile, and the pile head comprises a steel plate shell with a conical structure, and steel plate anchor bars and spiral stirrups are provided in the steel plate shell.

[0007] The present invention is suitable for pile driving construction in hard rock formations. It adopts a pile driving scheme of pre-drilling holes and then hammering pipe piles. It is safe, reliable and easy to construct, overcomes the disadvantages of traditional pile driving construction methods, is more economical and effective than traditional pile driving methods, and can be widely promoted in actual construction.

[0008] Compared with the prior art, the advantages of the present invention are as follows: 1) According to the geological conditions of the rock formation, the pile foundation boring equipment is selected, and the process parameters such as boring diameter, hole depth, hole wall roughness, etc. are optimized to effectively ensure the side friction resistance of the pile foundation, so that piles can be formed in soft rocks; 2) Reasonable control of hammer head weight and static pressure tonnage effectively avoids pile body cracks caused by pile head damage and / or sudden breakage of the pile body during pile delivery during traditional construction, thus ensuring construction quality and safety; 3) A pile head is provided at the head of the first section of prefabricated pipe piles, which improves the pile sinking speed of the pipe piles, effectively protects the integrity of the pipe piles, shortens the overall construction period, improves the overall construction quality, and effectively reduces the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a construction flow chart of the present invention. DETAILED DESCRIPTION

[0010] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific construction process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0011] like Figure 1 As shown, the method for sinking prefabricated pipe piles in rocks according to the present invention is suitable for construction of rock formations with a deformation model less than 20Mpa, and comprises the following steps: The first step is to measure and lay out the lines at the construction site to determine the location of the lead hole; The second step is to select a high-power rotary drilling rig as the pile foundation drilling equipment to carry out drilling and grouting; the rated power of the above-mentioned high-power rotary drilling rig is 350~410KW, the maximum hole diameter is 2 meters, and the hole depth is 60~90 meters.

[0012] The third step is to use a guide rod diesel pile hammer to lift the first section of prefabricated pipe pile into place. After checking and adjusting the pile position, the pile end is put into the soil and initially pressurized. At the same time, the verticality of the pile body is checked and corrected, and then the pile sinking operation is officially started. During this process, the verticality of the pile body is always observed and corrected; Step 4: When the top of the first section of prefabricated pipe pile is 0.5-1.0m away from the ground, lift the second section of prefabricated pipe pile to connect the piles, and then continue to sink the piles, and keep a record of the pressure value during this process; Step 5: Carry out pile driving of no more than 3 sections of prefabricated pipe piles according to step 4. For the last section of prefabricated pipe piles, at the end of the pile driving operation, it is necessary to use a guide rod diesel pile hammer for re-pressing, and the number of re-pressing times shall be at least three times. The settlement of the last re-pressing shall be controlled within 20mm, and a detailed and accurate record shall be made of the termination pile driving force.

[0013] After the prefabricated pipe pile is formed, the guide rod diesel pile hammer should be moved to the next station and the next prefabricated pipe pile should be driven according to the above steps. For dense pile groups, the pile driving sequence should be appropriate, such as skip driving every other pile or driving the middle pile first and then the surrounding piles, based on the actual situation on site. It should be pointed out that the hammer equipment, construction technology and process parameters (including pile driving force) of the engineering pile should be the same as those of the test pile.

[0014] In order to accurately control the direction of piling, a guide frame is provided on the pile frame below the guide rod type diesel pile hammer, so that the pile can be accurately penetrated into the stratum according to the designed direction to avoid deflection.

[0015] For moderately weathered rock strata, since it is difficult to form piles in this type of bearing layer, piling is difficult and the sediment problem is relatively serious, in order to better and more smoothly drive piles and improve the bearing capacity and avoid damage to the pipe piles during the pile sinking process, a pile head is provided at the head of the first section of the prefabricated pipe pile. The pile head includes a steel plate shell with a conical structure, and steel plate anchor bars and spiral stirrups are provided in the steel plate shell.

[0016] In addition, since the smooth progress of the pile driving operation is closely related to the hole guiding condition, for example, it is difficult to drive piles if the hole diameter is too small, and it is easy to cause broken piles if the hole wall is not smooth or the hole is tilted, the present invention optimizes the specific parameters of the hole guiding according to different rock formation conditions to ensure the smooth progress of the pile sinking work. Specifically: When the rock deformation model is less than 20Mpa, the depth of the guide hole is shorter than the length of the single-section prefabricated pipe pile by 500mm, and the inclination of the guide hole is less than 15% of the tangent value of the inclination angle.

[0017] The method for sinking prefabricated pipe piles in rocks disclosed by the present invention is more economical than the traditional method for sinking piles, and is convenient to construct, safe and reliable.

[0018] It should be noted that, in the description of the present invention, terms indicating orientation or positional relationships, such as "front", "rear", "left", "right", "vertical", "horizontal", "inside", "outside", etc., are based on customary expressions of orientation or positional relationships 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 should not be understood as a limitation on the present invention.

Claims

1. A method for sinking prefabricated pipe piles in rock, suitable for construction of rock formations with a deformation model less than 20Mpa, characterized in that: The steps include: The first step is to measure and lay out the lines at the construction site to determine the location of the lead hole; The second step is to use a high-power rotary drilling rig as the pile foundation drilling equipment to conduct drilling and grouting; The third step is to use a guide rod diesel pile hammer to lift the first section of prefabricated pipe pile into place. After checking and adjusting the pile position, the pile end is put into the soil and initially pressurized. At the same time, the verticality of the pile body is checked and corrected, and then the pile sinking operation is officially started. During this process, the verticality of the pile body is always observed and corrected; Step 4: When the top of the first section of prefabricated pipe pile is 0.5-1.0m away from the ground, lift the second section of prefabricated pipe pile to connect the piles, and then continue to sink the piles, and keep a record of the pressure value during this process; The fifth step is to carry out the pile sinking operation of other segments of prefabricated pipe piles according to step four until the piles are completed.

2. The method for sinking prefabricated pipe piles in rock according to claim 1, characterized in that: After the last section of prefabricated pipe piles are sunk, the guide rod type diesel pile hammer is used for re-pressing at least three times. The settlement amount of the last re-pressing is controlled within 20mm, and a detailed and accurate record is made of the termination pile driving force.

3. The method for sinking prefabricated pipe piles in rocks according to claim 1, characterized in that: A guide frame is arranged on the pile frame below the guide rod type diesel pile hammer.

4. The method for sinking prefabricated pipe piles in rock according to claim 1, characterized in that: The head of the first section of prefabricated pipe pile is provided with a pile head, and the pile head comprises a steel plate shell with a conical structure, and steel plate anchor bars and spiral stirrups are arranged in the steel plate shell.

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