Cast-in-place pile construction method based on dry salinized soil dry pore-forming

Abstract

The invention discloses a cast-in-place pile construction method based on dry hole forming of dry saline soil. The cast-in-place pile construction method comprises the steps that firstly, pile hole construction is conducted; secondly, a reinforcement cage is manufactured, specifically, the reinforcement cage is prefabricated, and a concrete protection layer round cake is arranged on the outer side of the reinforcement cage; mounting a protective cap at the tail end of the reinforcement cage; thirdly, a high-strength anti-corrosion soil engineering protection bag is installed on the outer side of the reinforcement cage in a cable-stayed sleeving mode or a vertical sleeving mode; fourthly, a plurality of anti-shearing pieces are installed in the pile hole, and each anti-shearing piece comprises a supporting rod and an anti-shearing head; cleaning the bottom of the pile hole; 5, pile filling operation is conducted, specifically, the reinforcement cage sleeved with the high-strength anti-corrosion soil engineering protection bag is hoisted into the pile hole, and the end of the high-strength anti-corrosion soil engineering protection bag is fixed and tensioned; and concrete is injected into the bottom of the pile hole through the grouting pipe to form the cast-in-place pile. According to the method, the cast-in-place pile can be constructed in the dry salinized soil, and the formed cast-in-place pile is high in structural stability and corrosion resistance, long in service life, easy and convenient to construct and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of cast-in-place pile construction, and particularly relates to a construction method for cast-in-place piles based on dry hole formation in arid saline soil. Background Art

[0002] The anti-corrosion problems of steel structures and concrete in saline soil areas have always been the research and development goals of construction industry personnel. Steel and concrete are the main bodies of various important buildings at present. The structures exposed on the ground can achieve anti-corrosion through the method of regularly brushing various anti-corrosion materials, while the anti-corrosion of underground projects is more difficult. Because the components are in direct contact with strongly corrosive saline soil and brine, and it is impossible to regularly brush anti-corrosion materials. There are large areas of salt lakes distributed in the northwest region of China, where rich mineral resources and chemical raw materials are stored, and there are also large areas of saline soil foundations that are not conducive to construction. The industrial and civil buildings of mining enterprises and chemical enterprises here, as well as railways and high-grade highways, need to be built on these saline soil foundations. The saline soil rich in brine is widely distributed with a large thickness, and the mechanical strength of the foundation soil is low and the compressibility is high. All buildings must adopt artificial foundations or pile foundations; important buildings and railway and highway bridges must adopt reinforced concrete cast-in-place pile foundations. Since the saline soil foundation soil contains brine with sulfate radicals and chloride ions that are strongly corrosive to building materials such as steel and concrete. Therefore, it is particularly urgent to develop a pile body with high efficiency and low cost for anti-corrosion. Summary of the Invention

[0003] The purpose of the present invention is to provide a construction method for cast-in-place piles based on dry hole formation in arid saline soil. This method can construct cast-in-place piles in arid saline soil, and the formed cast-in-place piles have strong structural stability and corrosion resistance, long service life, simple and convenient construction, and low cost.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A construction method for cast-in-place piles based on dry hole formation in arid saline soil, the construction method comprising the following steps: Step 1, pile hole construction; Step 2, making the steel reinforcement cage. The steel reinforcement cage is prefabricated according to the size of the cast-in-place pile, and a plurality of concrete protection layer round cakes are uniformly arranged on the outer side of the steel reinforcement cage; protection caps are installed on each steel bar at the end of the steel reinforcement cage; Step 3, installing the high-strength anti-corrosion geotextile bag. The high-strength anti-corrosion geotextile bag is installed on the outer side of the steel reinforcement cage by means of diagonal tension sleeve-in or vertical sleeve-in; Step 4, installing shear-resistant members. A number of shear-resistant members are installed in the pile hole. The shear-resistant members include support rods installed in the side wall of the pile hole and shear-resistant heads fixedly installed at the ends of the support rods; after all the shear-resistant members are installed, the bottom of the pile hole is cleaned; Step 5, bored pile operation: Hoist the steel reinforcement cage with a high-strength anti-corrosion geotextile protection bag into the pile hole, and fix and tension the end of the high-strength anti-corrosion geotextile protection bag; Install a grouting pipe in the middle of the steel reinforcement cage, and pour concrete into the bottom of the pile hole through the grouting pipe to form a bored pile.

[0005] Preferably, in step 1, manual hole formation or mechanical dry operation hole formation is adopted, and the pile hole is cylindrical.

[0006] Preferably, in step 3, for the inclined pulling and sleeving method, first set a first lifting point at the middle and lower part outside the steel reinforcement cage, lift the bottom of the steel reinforcement cage through the first lifting point to be in an inclined state, and then sleeve the high-strength anti-corrosion geotextile protection bag outside the steel reinforcement cage; Then set a second lifting point at the top position outside the steel reinforcement cage, lift the top of the steel reinforcement cage through the second lifting point to be in an inclined state, and then pull the sleeved high-strength anti-corrosion geotextile protection bag to the top of the steel reinforcement cage to complete the installation of the high-strength anti-corrosion geotextile protection bag.

[0007] Preferably, for the vertical sleeving method, first install a lifting support on the top of the steel reinforcement cage, install multiple pulleys on the circumference of the lifting support, install multiple control ropes on the top of the high-strength anti-corrosion geotextile protection bag, and one end of the control rope bypasses the pulley; Use a lifting device to lift the entire steel reinforcement cage to a vertical state, and pull the control rope to sleeve the high-strength anti-corrosion geotextile protection bag outside the steel reinforcement cage.

[0008] Preferably, in step 4, first install a pile sheath in the pile hole, one end of the shear-resistant member is located inside the pile sheath, and the other end of the shear-resistant member passes through the pile sheath and is connected to the side wall of the pile hole.

[0009] Preferably, the support rod is inclined or horizontal.

[0010] Preferably, the diameter of the high-strength anti-corrosion geotextile protection bag is slightly larger than the diameter of the pile hole, and the length of the high-strength anti-corrosion geotextile protection bag is greater than the depth of the pile hole.

[0011] In the present invention, the inclined pulling and sleeving method or the vertical sleeving method adopted can quickly sleeve the high-strength anti-corrosion geotextile protection bag outside the steel reinforcement cage, with high construction efficiency. The set concrete protection layer discs can prevent the infiltration of moist gas and water, avoid the corrosion and expansion of steel bars, thereby protecting the concrete structure, extending the service life, having an anchoring force on the steel bars, making the steel bars and concrete closely combined, jointly bearing external forces such as axial force and bending moment, and enhancing the stability of the structure. The set protection cap improves the anti-corrosion ability of the end of the steel bar. The set shear-resistant member can effectively improve the connection strength between the bored pile and the side wall of the pile hole, ensure the stability of the overall structure, and reduce the settlement amount during subsequent use. When the foundation soil is relatively soft, structural strengthening is also carried out by installing a pile sheath to improve stability. Description of the Drawings

[0012] Figure 1 Schematic diagram of the completed overall structure construction of the present invention; Figure 2 Schematic diagram of the shear-resistant member structure of the present invention; Figure 3 Schematic diagram of the construction state of Step Five of the present invention; Figure 4 Schematic diagram of the vertical insertion installation method in Step Three of the present invention; Figure 5 Schematic diagram of the hoisting state of the first lifting point in the diagonal pulling and inserting type in Step Three of the present invention; Figure 6 Schematic diagram of the hoisting state of the second lifting point in the diagonal pulling and inserting type in Step Three of the present invention; Figure 7 Schematic diagram of the completed construction effect of another embodiment of the overall structure of the present invention; In the figure: 1, steel reinforcement cage; 2, concrete protection layer round cake; 3, protection cap; 4, high-strength anti-corrosion geotextile protection bag; 5, lifting bracket; 6, pulley; 7, control rope; 8, shear-resistant member; 9, pile sheath; 10, grouting pipe; 80, support rod; 81, shear-resistant head. Specific embodiments

[0013] The following further describes the present invention in conjunction with the accompanying drawings: As Figures 1 to 7 shown, a construction method for bored cast-in-place piles based on dry bored holes in arid saline soil, the construction method includes the following steps: Step One, pile hole construction; manual hole formation or mechanical dry operation hole formation is adopted, and the pile hole is cylindrical. When the diameter size of the pile hole is smaller than the minimum space required for manual operation, only mechanical dry operation can be used to form the hole. In this case, mechanical equipment needs to be used to assist in installing the shear-resistant member in Step Four. In this embodiment, the diameter size of the pile hole is not smaller than the minimum space required for manual operation, and both manual hole formation and mechanical dry operation can be used for operation.

[0014] Step Two, fabrication of the steel reinforcement cage 1. The steel reinforcement cage 1 is prefabricated according to the size of the bored cast-in-place pile. A plurality of concrete protection layer round cakes 2 are uniformly arranged on the outer side of the steel reinforcement cage 1. The concrete protection layer round cakes 2 can prevent the infiltration of humid gas and water, avoid the corrosion and expansion of the steel bars, thereby protecting the concrete structure, extending the service life, having an anchoring force on the steel bars, enabling the steel bars and the concrete to be closely combined, jointly bearing external forces such as axial force and bending moment, and enhancing the stability of the structure. A protection cap 3 is installed on the end of each steel bar at the end of the steel reinforcement cage 1. The protection cap 3 can not only prevent scratching of the high-strength anti-corrosion geotextile protection bag 4 during the installation of the high-strength anti-corrosion geotextile protection bag 4, but also avoid damage to the anti-rust layer on the surface of the steel bar, thereby ensuring the mechanical properties of the steel bar and ensuring that the steel reinforcement cage 1 can normally play a bearing role in the underground structure. An anti-rust and corrosion-resistant coating is applied to the outer surface of the steel bars of the steel reinforcement cage 1.

[0015] Step 3: Installation of the high-strength anti-corrosion geotextile bag 4. The high-strength anti-corrosion geotextile bag 4 is installed outside the steel reinforcement cage 1 in an inclined pulling and sleeving manner or a vertical sleeving manner. The diameter of the high-strength anti-corrosion geotextile bag 4 is slightly larger than the diameter of the pile hole, and the length of the high-strength anti-corrosion geotextile bag 4 is greater than the depth of the pile hole. When pouring concrete, ensure that the high-strength anti-corrosion geotextile bag 4 fits as closely as possible to the pile hole to ensure the stability of the overall structure of the cast-in-place pile.

[0016] In the inclined pulling and sleeving manner, first set a first lifting point at the middle and lower part outside the steel reinforcement cage 1. Pull up the bottom of the steel reinforcement cage 1 through the first lifting point to make it inclined, and then sleeve the high-strength anti-corrosion geotextile bag 4 from the bottom of the steel reinforcement cage 1 to the outside of the steel reinforcement cage 1; then set a second lifting point at the top position outside the steel reinforcement cage 1. Let the bottom of the steel reinforcement cage 1 touch the ground, pull up the top of the steel reinforcement cage 1 through the second lifting point to make it inclined, and then pull the sleeved high-strength anti-corrosion geotextile bag 4 to the top of the steel reinforcement cage 1 to complete the installation of the high-strength anti-corrosion geotextile bag 4. This method can complete the sleeving of the high-strength anti-corrosion geotextile bag 4 without lifting the entire steel reinforcement cage 1, and the operation is simple and convenient.

[0017] In the vertical sleeving manner, first install a lifting support 5 at the top of the steel reinforcement cage 1, install a plurality of pulleys 6 on the circumference of the lifting support 5, install a plurality of control ropes 7 at the top of the high-strength anti-corrosion geotextile bag 4, and one end of each control rope 7 respectively bypasses a pulley 6 and is located at the outside bottom of the steel reinforcement cage 1; then use a lifting device to lift the entire steel reinforcement cage 1 into a vertical state, and the operator pulls the control ropes 7 to sleeve the high-strength anti-corrosion geotextile bag 4 from the bottom up outside the steel reinforcement cage 1.

[0018] Step 4: Installation of the shear-resistant parts 8. Install a number of shear-resistant parts 8 in the pile hole. The shear-resistant parts 8 include a support rod 80 installed in the side wall of the pile hole and a shear-resistant head 81 fixedly installed at the end of the support rod 80; after all the shear-resistant parts 8 are installed, clean the bottom of the pile hole. The support rod 80 is inclined or horizontal. In this embodiment, the support rod 80 is inclined downward, and the shear-resistant head 81 contacts the high-strength anti-corrosion geotextile bag 4. When pouring concrete, the shear-resistant head 81 makes the high-strength anti-corrosion geotextile bag 4 partially concave inward and stuck on the formed cast-in-place pile to form a shear-resistant effect. The shear-resistant head 81 is a round pipe, an arc-shaped connector or a U-shaped protrusion. Of course, this step can also be constructed and installed synchronously during the construction of the pile hole in Step 1. The support rod 80 is a steel bar with a sharp tip at the front end, which is convenient for inserting into the soil. When installing, first drill an installation hole in the pile hole. In a preferred embodiment, a spiral structure is arranged on the outside of the support rod 80, and it can be directly installed by screwing, which improves the installation efficiency.

[0019] When the foundation soil is relatively soft, first install the pile sheath 9 in the pile hole. One end of the shear-resistant member 8 is located inside the pile sheath 9, that is, the shear head 81 is located inside the pile sheath 9 and contacts the high-strength anti-corrosion geotextile bag 4, which is used to improve the shear resistance. The other end of the shear-resistant member 8 passes through the pile sheath 9 and is connected to the side wall of the pile hole, so that the pile sheath 9 is tightly fixedly connected to the foundation soil, improving the stability of the cast-in-place pile and reducing the settlement amount.

[0020] Step Five, carry out the cast-in-place pile operation. Hoist the steel reinforcement cage 1 sleeved with the high-strength anti-corrosion geotextile bag 4 into the pile hole, and fixedly tension the top end of the high-strength anti-corrosion geotextile bag 4 at the mouth of the pile hole. Install a grouting pipe 10 in the middle of the steel reinforcement cage 1, and pour concrete to the bottom of the pile hole through the grouting pipe 10 to form a cast-in-place pile. The grouting pipe 10 can either be poured by means of high-pressure grouting or a hopper can be installed at the top of the grouting pipe 10, and grouting is carried out through the hopper and the pressure difference to form a cast-in-place pile and correct the top of the cast-in-place pile.

[0021] The above embodiments are only several descriptions of the concept and implementation of the present invention, and are not intended to limit it. Under the concept of the present invention, technical solutions without substantial transformation are still within the protection scope.

Claims

1. A construction method for cast-in-place piles based on dry hole formation in arid saline soil, characterized in that: The construction method includes the following steps: Step 1, pile hole construction; Step 2, making the steel reinforcement cage. Precast the steel reinforcement cage according to the size of the cast-in-place pile, and evenly arrange a plurality of concrete protection layer discs on the outer side of the steel reinforcement cage; install protection caps on each steel bar at the end of the steel reinforcement cage. Step 3, installing the high-strength anti-corrosion geotextile bag. Install the high-strength anti-corrosion geotextile bag on the outer side of the steel reinforcement cage in a way of inclined pulling and sleeving or vertical sleeving. Step 4, installing shear-resistant parts. Install several shear-resistant parts in the pile hole. The shear-resistant parts include support rods installed in the side wall of the pile hole and shear-resistant heads fixedly installed at the ends of the support rods; after all the shear-resistant parts are installed, clean the bottom of the pile hole. Step 5, cast-in-place pile operation. Hoist the steel reinforcement cage with the high-strength anti-corrosion geotextile bag into the pile hole, and fix and tension the end of the high-strength anti-corrosion geotextile bag; install a grouting pipe in the middle of the steel reinforcement cage, and pour concrete to the bottom of the pile hole through the grouting pipe to form a cast-in-place pile.

2. The construction method of the cast-in-place pile based on dry hole formation in arid saline soil according to claim 1, wherein: In Step 1, manual hole forming or mechanical dry operation hole forming is adopted, and the pile hole is cylindrical.

3. The construction method of cast-in-place pile based on dry hole formation in arid saline soil according to claim 1 or 2, characterized in that: In Step 3, for the inclined pulling and sleeving method, first set a first lifting point in the middle and lower part on the outer side of the steel reinforcement cage, pull up the bottom of the steel reinforcement cage through the first lifting point to make it inclined, and then sleeve the high-strength anti-corrosion geotextile bag onto the outer side of the steel reinforcement cage; then set a second lifting point at the top position on the outer side of the steel reinforcement cage, pull up the top of the steel reinforcement cage through the second lifting point to make it inclined, and then pull the sleeved high-strength anti-corrosion geotextile bag to the top of the steel reinforcement cage to complete the installation of the high-strength anti-corrosion geotextile bag.

4. The construction method of cast-in-place pile based on dry hole formation in arid saline soil according to claim 1 or 2, characterized in that: For the vertical sleeving method, first install a lifting bracket at the top of the steel reinforcement cage, install a plurality of pulleys on the circumference of the lifting bracket, install a plurality of control ropes at the top of the high-strength anti-corrosion geotextile bag, and one end of the control rope bypasses the pulley; use a lifting device to lift the whole steel reinforcement cage into a vertical state, and pull the control rope to sleeve the high-strength anti-corrosion geotextile bag on the outer side of the steel reinforcement cage.

5. The construction method of cast-in-place pile based on dry hole formation in arid saline soil according to claim 1, characterized in that: In Step 4, first install a pile sheath in the pile hole, one end of the shear-resistant part is located inside the pile sheath, and the other end of the shear-resistant part passes through the pile sheath and is connected to the side wall of the pile hole.

6. The construction method of cast-in-place pile based on dry hole formation in arid saline soil according to claim 1 or 5, characterized in that: The support rod is inclined or horizontally arranged.

7. The construction method of cast-in-place pile based on dry hole formation in arid saline soil according to claim 6, characterized in that: The diameter of the high-strength anti-corrosion geotextile bag is slightly larger than the diameter of the pile hole, and the length of the high-strength anti-corrosion geotextile bag is greater than the depth of the pile hole.

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