阅读说明：本技术 一种重复施工利用超长钢护筒的方法 (Method for repeatedly constructing and utilizing ultra-long steel casing ) 是由 李莉华 袁忠海 刘杰 向阳 包利剑 黄思权 于 2019-09-06 设计创作，主要内容包括：一种重复施工利用超长钢护筒的方法,包括步骤：1)选择内径大于设计桩直径的定位钢护筒,预埋深度≥1000mm,与设计桩同心设置；2)在定位钢护筒范围内冲第一段孔至稳定岩层表面,第一段孔的孔径大于钻孔设计值；3)选择直径小于第一段孔的孔径且大于钻孔设计值的超长钢护筒,垂直进入第一段孔中且支承于稳定岩层表面上；4)继续冲孔径为钻孔设计值的第二段孔进入稳定岩层,至设计深度；5)清孔至第二段孔符合设计要求为止；6)吊放钢筋笼至设计位置后,支护于超长钢护筒上；7)进行混凝土浇灌作业；8)混凝土浇灌完毕2h内,采用振动锤以1.5m/min的速度将超长钢护筒拨出；9)至超长钢护筒下端拨出至定位钢护筒,取下振动锤,将超长钢护筒拨出。(A method for repeatedly constructing and utilizing an ultra-long steel casing comprises the following steps: 1) selecting a positioning steel casing with the inner diameter larger than the diameter of the designed pile, wherein the embedded depth is more than or equal to 1000mm, and the positioning steel casing and the designed pile are arranged concentrically; 2) punching a first section of hole to the surface of a stable rock stratum within the range of the positioning steel casing, wherein the aperture of the first section of hole is larger than the designed drilling value; 3) selecting an ultra-long steel casing with the diameter smaller than the aperture of the first section of hole and larger than the designed value of drilling, vertically entering the first section of hole and supporting on the surface of a stable rock stratum; 4) continuously punching a second section of hole with the hole diameter being the designed value of the drilling hole into the stable rock stratum to the designed depth; 5) cleaning the hole until the second section of hole meets the design requirement; 6) after the reinforcement cage is hoisted to the designed position, the reinforcement cage is supported on the ultra-long steel casing; 7) carrying out concrete pouring operation; 8) within 2h after the concrete pouring is finished, pulling out the ultra-long steel casing by adopting a vibration hammer at the speed of 1.5 m/min; 9) and pulling out the lower end of the super-long steel protection cylinder to the positioning steel protection cylinder, taking down the vibration hammer, and pulling out the super-long steel protection cylinder.)

1. A method for repeatedly constructing and utilizing an ultra-long steel casing is characterized by comprising the following steps:

1) selecting a positioning steel pile casing according to the position and the size of a designed pile, wherein the inner diameter of the positioning steel pile casing is larger than the diameter of the designed pile, the embedded depth of the positioning steel pile casing is more than or equal to 1000mm, the positioning steel pile casing is higher than the ground and is arranged concentrically with the designed pile;

2) According to a conventional process, downwards punching a first section of hole to the surface of a stable rock stratum within the range of the positioning steel casing, wherein the aperture of the first section of hole is larger than the designed value of drilling, and when punching the first section of hole, hole wall maintenance is carried out by adopting the conventional process;

3) Selecting an ultra-long steel casing, wherein the diameter of the ultra-long steel casing is smaller than the aperture of the first section of hole and larger than the designed value of drilling, vertically hoisting the ultra-long steel casing by using a crane until the plane position and the verticality are adjusted to be within the standard deviation range, controlling the ultra-long steel casing to enter the first section of hole, and supporting the ultra-long steel casing on the surface of a stable rock stratum;

4) Continuously downwards punching a second section of hole to enter the stable rock stratum to a designed depth, wherein the aperture of the second section of hole is a drilling design value;

5) cleaning the holes by adopting a reverse circulation slurry placement method of a slurry pump until the sediment thickness, the slurry proportion and the sand content of the second section of holes meet the design requirements;

6) After hole cleaning is finished, hoisting a reinforcement cage to a designed position, and supporting on the ultra-long steel casing;

7) After the thickness of the sediment at the bottom of the self-checking hole meets the design requirement, a guide pipe method is adopted for carrying out concrete pouring operation, when pouring is started, the height from the free end of the guide pipe to the bottom of the second section of hole is 0.3-0.5m, the concrete adopts underwater self-compacting concrete, after pouring is started, the guide pipe rises, and the free end of the guide pipe is positioned below the concrete surface;

8) Within 2h after the concrete pouring, the ultra-long steel casing is pulled out slowly by a vibration hammer, the pulling-out speed is controlled to be 1.5m/min, and the concrete surface falling data in the ultra-long steel casing is monitored;

9) And (4) pulling out the lower end of the super-long steel pile casing to a positioning steel pile casing, taking down the vibration hammer, and pulling out the super-long steel pile casing by adopting a crane for carrying away for repeated construction and utilization.

2. The method of claim 1, wherein: the length of the positioning steel casing in the step 1) is 1.2m, and the inner diameter of the positioning steel casing is 400mm larger than the diameter of the designed pile.

3. The method of claim 1, wherein: and 2) circularly replacing the deposited slurry generated in the punching process by using low-density slurry when the first section of hole is punched.

4. the method of claim 1, wherein: and 3) the diameter of the ultra-long steel casing is 200mm smaller than the aperture of the first section of hole.

5. The method of claim 1, wherein: and 3) when the ultra-long steel casing enters the first section of hole, after the ultra-long steel casing sinks stably due to self weight, hoisting a vibration hammer to the upper end of the ultra-long steel casing and centering, and impacting the ultra-long steel casing to stably support on the surface of a stable rock stratum.

6. The method of claim 1, wherein: and 5) supplementing the slurry after the sediment thickness is less than 5cm and the slurry pump is used for cleaning the hole by a reverse circulation slurry placement method, keeping the height of the slurry in the first section of hole to be more than 1.5-2m of the underground water level or the surface water level, wherein the specific gravity of the slurry is 1.1-1.2, the sand content is less than 4%, the viscosity is 17-20s, and the pH value of the slurry is 6-8.

7. the method of claim 1, wherein: and 7) pouring concrete in the concrete pouring operation in the step 7), wherein the poured concrete amount is larger than the designed pouring amount.

8. the method of claim 1, wherein: and 8) the vibration hammer is an electric vibration hammer.

Technical Field

The invention relates to the field of constructional engineering, in particular to a method for repeatedly constructing and utilizing an ultra-long steel casing.

Background

The geology of coastal areas and the like in China is complex, the sand layer has wide distribution range and large thickness, the rock surface has large fluctuation and high water level, and unfavorable geological conditions such as the development of the sloping rocks and the karst are common. The most economical hole forming mode of engineering projects under the geological conditions is a punched pile pouring system, and in order to avoid hole collapse of a hole pile when a hole channel is too deep or the geology is complex, a whole-course steel casing follow-up mode is generally selected for hole forming. The steel sleeve is left in the foundation after the hole is formed, steel is seriously wasted, and the construction cost is high.

Disclosure of Invention

the invention aims to provide a method for repeatedly constructing and utilizing an ultra-long steel casing, aiming at the defects of the prior art, the ultra-long steel casing is pulled out for repeated construction and utilization on the premise of ensuring the quality of a pile body, and the construction cost is effectively reduced.

The technical scheme of the invention is as follows: a method for repeatedly constructing and utilizing an ultra-long steel casing comprises the following steps:

1) Selecting a positioning steel pile casing according to the position and the size of a designed pile, wherein the inner diameter of the positioning steel pile casing is larger than the diameter of the designed pile, the embedded depth of the positioning steel pile casing is more than or equal to 1000mm, the positioning steel pile casing is higher than the ground and is arranged concentrically with the designed pile;

2) According to a conventional process, downwards punching a first section of hole within the range of the positioning steel casing to the surface of a stable rock stratum, wherein the aperture of the first section of hole is larger than the designed value of drilling, and when punching the first section of hole, hole wall maintenance is carried out by adopting the conventional process;

3) Selecting an ultra-long steel casing, wherein the diameter of the ultra-long steel casing is smaller than the aperture of the first section of hole and larger than the designed value of drilling, vertically hoisting the ultra-long steel casing by using a crane until the plane position and the verticality are adjusted to be within the standard deviation range, controlling the ultra-long steel casing to enter the first section of hole, and supporting the ultra-long steel casing on the surface of a stable rock stratum;

4) Continuously downwards punching a second section of hole to enter the stable rock stratum to a designed depth, wherein the aperture of the second section of hole is a drilling design value;

5) Cleaning the holes by adopting a reverse circulation slurry placement method of a slurry pump until the sediment thickness, the slurry proportion and the sand content of the second section of holes meet the design requirements;

6) After hole cleaning is finished, hoisting a reinforcement cage to a designed position, and supporting on the ultra-long steel casing;

7) after the thickness of the sediment at the bottom of the self-checking hole meets the design requirement, a guide pipe method is adopted for carrying out concrete pouring operation, when pouring is started, the height from the free end of the guide pipe to the bottom of the second section of hole is 0.3-0.5m, the concrete adopts underwater self-compacting concrete, after pouring is started, the guide pipe rises, and the free end of the guide pipe is positioned below the concrete surface;

8) Within 2h after the concrete pouring, the ultra-long steel casing is pulled out slowly by a vibration hammer, the pulling-out speed is controlled to be 1.5m/min, and the concrete surface falling data in the ultra-long steel casing is monitored;

9) And (4) pulling out the lower end of the super-long steel pile casing to a positioning steel pile casing, taking down the vibration hammer, and pulling out the super-long steel pile casing by adopting a crane for carrying away for repeated construction and utilization.

The length of the positioning steel casing in the step 1) is 1.2m, and the inner diameter of the positioning steel casing is 400mm larger than the diameter of the designed pile.

And 2) circularly replacing the deposited slurry generated in the punching process by using low-density slurry when the first section of hole is punched.

and 3) the diameter of the ultra-long steel casing is 200mm smaller than the aperture of the first section of hole.

and 3) when the ultra-long steel casing enters the first section of hole, after the ultra-long steel casing sinks stably due to self weight, hoisting a vibration hammer to the upper end of the ultra-long steel casing and centering, and impacting the ultra-long steel casing to stably support on the surface of a stable rock stratum.

And 5) supplementing the slurry after the sediment thickness is less than 5cm and the slurry pump is used for cleaning the hole by a reverse circulation slurry placement method, keeping the height of the slurry in the first section of hole to be more than 1.5-2m of the underground water level or the surface water level, wherein the specific gravity of the slurry is 1.1-1.2, the sand content is less than 4%, the viscosity is 17-20s, and the pH value of the slurry is 6-8.

And 7) pouring concrete in the concrete pouring operation in the step 7), wherein the poured concrete amount is larger than the designed pouring amount.

and 8) the vibration hammer is an electric vibration hammer.

Adopt above-mentioned technical scheme to have following beneficial effect:

1. The method for repeatedly constructing and utilizing the ultra-long steel casing can pre-embed the positioning steel casing at the position of the designed pile in advance, so that the pile position is fixed in advance, and the positioning is accurate. In the subsequent repeated punching construction process, the first section of hole and the second section of hole do not deviate, the punching precision is high, repeated radioactive rays of constructors are not needed, and the labor intensity of the constructors is effectively reduced.

2. The method for repeatedly constructing and utilizing the ultra-long steel casing has the advantages that the ultra-long steel casing and the positioning steel casing can be repeatedly constructed and used, and compared with the traditional construction method for once putting the steel casing, the method improves the use times of the steel casing, and effectively saves steel resources and energy.

3. the method for repeatedly constructing and utilizing the ultra-long steel casing has the advantages of high system strength, high rigidity, stable quality of the formed designed pile and better verticality, and effectively meets the construction requirements.

4. The method for repeatedly constructing and utilizing the ultra-long steel casing has the advantages that the embedded depth of the positioning steel casing is more than or equal to 1000mm and is higher than the ground, so that the positioning steel casing is stably positioned, the target is obvious, a constructor can conveniently punch holes within the range of the positioning steel casing, in addition, the section of the positioning steel casing higher than the ground is also used for enclosing and blocking slurry generated by punching, and a slurry pump is conveniently arranged.

5. The method for repeatedly constructing and utilizing the ultra-long steel casing has the advantages that when the concrete is poured, the height from the free end of the guide pipe to the bottom of the second section of hole is 0.3-0.5m, so that the poured concrete extrudes mud deposited in the second section of hole and the first section of hole, the quality of the poured concrete is ensured, after the pouring is started, the guide pipe rises, the free end of the guide pipe is positioned below the concrete surface, and the pouring pressure of the concrete is reduced on the premise of keeping the mud smoothly extruded.

6. The method for repeatedly constructing and utilizing the ultra-long steel casing comprises the steps of adopting a vibration hammer to pull out the ultra-long steel casing at a low speed within 2 hours after concrete pouring, controlling the pulling-out speed to be 1.5m/min, using the vibration hammer to pull out the ultra-long steel casing and hammer the ultra-long steel casing at the same time, and if the pulling-out speed is too low, although concrete can be effectively tamped, the risk that the ultra-long steel casing cannot be pulled out due to concrete solidification exists, and if the pulling-out speed is too high, the tamping time for the concrete is too short, so that the defects of gaps, cracks and the like of the formed concrete can be caused, and the formed pile body is scrapped when the concrete is serious.

the following further description is made with reference to the accompanying drawings and detailed description.

drawings

FIG. 1 is a schematic view of the construction of the present invention.

In the attached drawing, 1 is a positioning steel casing, 2 is a first section of hole, 3 is an ultra-long steel casing, and 4 is a second section of hole.

Detailed Description

in the invention, the construction method which is not marked adopts the conventional construction method in the building field for construction, and the raw material which is not marked with specific cost usually adopts the conventional raw material in the building field.