Complex karst geology rotary drilling hole-forming secant pile and construction method

Abstract

The construction method comprises the following steps that a foundation pit is divided into a light load area and a heavy load area according to the magnitude of the soil pressure load on the outer side of a supporting structure, and a load partition reinforcement arrangement optimization system is designed and determined; i-sequence short piles are constructed, an integrated rotary excavating drill bit driving system is adopted to drive a steel casing and excavate to form a hole, concrete is poured, and the steel casing is pulled out; and a second-order long pile is constructed, and the integrated rotary excavating drill bit driving system is adopted for driving a steel casing and excavating to form a hole. The integrated rotary excavating drill bit driving system has the beneficial effects that the integrated rotary excavating drill bit driving system is adopted, and integration of drilling and soil taking construction equipment is achieved; a steel casing deformation supporting system is adopted, and rapid supporting of the deformed steel casing is achieved; a karst area concrete anti-loss system is adopted, so that the inner-layer iron gauze is conveniently mounted; a load partition reinforcement arrangement optimization system is adopted, the stability and impermeability of the secant pile supporting structure are improved, and efficient utilization of materials is improved.

Claims

1. A complex karst geological rotary drilling hole bite pile, characterized in that: include: Integrated rotary drilling bit drive system, steel casing deformation support system, karst area concrete loss prevention system and load zone reinforcement optimization system; A rotary drilling rig is placed in the foundation pit, and the rotary drilling rig is connected with a power head along the rotary drilling direction. The first section of steel casing is inserted at the bottom of the foundation pit, and the bottom end of the first section of steel casing is provided with casing cutting teeth; the rotary drill is provided with a drilling hole in the first section of steel casing; the steel casing deformation support system includes an umbrella-shaped support device; there is a cave under the foundation pit, a steel casing is arranged in the borehole, and the side wall of the steel casing has a steel casing deformation section, the outer wall of the steel casing deformation section is fitted with a cave, and the inner wall is supported by an umbrella-shaped support device; a pedestal is placed flat outside the borehole, and the karst area concrete loss prevention system is placed on the pedestal; the foundation pit is divided into a light load area and a heavy load area, and a load zoning reinforcement optimization system is provided. A grouting pipe is provided on the top of the load-zone reinforcement optimization system.

2. The complex karst geological rotary drilling and biting pile according to claim 1 is characterized in that: When constructing sequence I short piles, the integrated rotary drilling bit driving system includes a driving connection plate and a steel casing driver, the bottom of the power head is connected to the driving connection plate, the bottom of the driving connection plate is connected to the steel casing driver, and the bottom of the steel casing driver is connected to the first section of steel casing; when constructing sequence II long piles, the integrated rotary drilling bit driving system includes a rotary drilling drill rod and a rotary drilling bit, the bottom of the power head is connected to the rotary drilling drill rod along the central axis direction, the bottom of the rotary drilling drill rod is connected to the rotary drilling bit, and the bottom end of the rotary drilling bit is provided with drill bit cutting teeth.

3. The complex karst geological rotary drilling occlusal pile according to claim 1 is characterized in that: The umbrella-shaped supporting device comprises a main pole; the main pole is a hollow structure, a plurality of sliding blocks are sleeved on the outer wall of the main pole, a movable pulley is arranged inside the sliding block, a limit block is arranged on the top of the sliding block, and the limit block is fixed on the outer wall of the main pole; a fixed pulley is arranged inside the lower end of the main pole, and a thin rope, a third spring, a U-shaped switch, a hook, a reed and a lever are arranged inside the upper end; a button is arranged on the outer wall of the upper end of the main pole; the thin rope is connected with the hook, the fixed pulley and the movable pulley in sequence; the thin rope connected between the hook and the fixed pulley is wrapped with a second spring, and the second spring sleeve is provided with a plastic hose.

4. The complex karst geological rotary drilling and occlusal pile according to claim 3 is characterized in that: The umbrella-shaped supporting device comprises an upper umbrella steel frame and a lower umbrella steel frame; the upper umbrella steel frame is a hollow structure and is symmetrically arranged on both sides of the main pole. A first spring is arranged in the upper umbrella steel frame, and the end of the first spring is connected to a supporting rod; the lower umbrella steel frame is connected between the sliding block and the upper umbrella steel frame.

5. The complex karst geological rotary drilling and biting pile according to claim 1 is characterized in that: The karst area concrete loss prevention system includes a steel cage, an outer wire mesh, an inner wire mesh and buckles; the outer wire mesh is wrapped around the outer wall of the steel cage, and the inner wire mesh is tightly attached to the inner wall of the steel cage; the steel cage is provided with main bars and stirrups, and the outer wire mesh and the inner wire mesh are connected to the main bars and stirrups by buckles; the inner wire mesh is longer than the outer wire mesh, and the mesh diameter of the inner wire mesh is larger than that of the outer wire mesh; anti-floating strips are provided inside the steel cage.

6. The complex karst geological rotary drilling and biting pile according to claim 1 is characterized in that: There are waterproof layers and karst layers under the foundation pit bottom; the load-zone reinforcement optimization system includes I-sequence short piles, II-sequence long piles, main reinforcement and rectangular steel cage; I-sequence short piles include the first I-sequence short piles and the second I-sequence short piles; The II-sequence long piles include the first II-sequence long piles and the second II-sequence long piles; the main reinforcement includes the first main reinforcement and the second main reinforcement; the bottoms of the I-sequence short piles are all located in the waterproof layer, and the bottoms of the II-sequence long piles are all located in the karst layer; grouting pipes are provided between the first I-sequence short pile and the first II-sequence long pile, and between the second I-sequence short pile and the second II-sequence long pile, and the grouting pipes are arranged between the first main reinforcement or the second main reinforcement.

7. The complex karst geological rotary drilling occlusal pile according to claim 6 is characterized in that: The first-order short piles and the first-order long piles are interlocked as the supporting structure of the light-load area of ​​the foundation pit, and the second-order short piles and the second-order long piles are interlocked as the supporting structure of the heavy-load area of ​​the foundation pit; a cap beam is provided on the top of the supporting structure; the first main reinforcement is arranged inside the first-order long piles, and the second main reinforcement is arranged inside the second-order long piles, and the main reinforcement adopts non-uniform reinforcement at angles of α and β; the rectangular steel cage is arranged inside the second-order short piles.

8. The method for constructing interlocking piles in complex karst geology by rotary drilling and hole drilling as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Divide the foundation pit into light load area and heavy load area according to the soil pressure load outside the supporting structure, and design and determine the load zone reinforcement optimization system; Step 2: construct the first-order short piles, use the integrated rotary drilling rig drive system to drive the steel casing and dig holes, pour concrete, and remove the steel casing; Step 3: construct the long piles of sequence II, use the integrated rotary drill bit drive system to drive the steel casing and excavate the hole; when the steel casing in the karst area is partially deformed, use the steel casing deformation support system; Lower the umbrella-shaped support device to the deformation section of the steel casing and support it inside the deformation section of the steel casing; Make a karst area concrete anti-loss system on the pedestal, install the karst area concrete anti-loss system into the load-dividing reinforcement optimization system, pre-embed the grouting pipe, pour the concrete, and remove the steel casing; Step 4: Repeat the above steps 2 and 3 to form an interlocking pile support structure.

9. The complex karst geological rotary drilling and interlocking pile construction method according to claim 8 is characterized in that: In step three, the umbrella-shaped supporting device includes a main pole, an upper umbrella steel frame and a lower umbrella steel frame; a thin rope, a third spring, a U-shaped switch, a hook, a spring leaf and a lever are arranged inside the upper end of the main pole; a button is arranged on the outer wall of the upper end of the main pole; a second spring is wrapped around the thin rope; a plurality of sliding blocks are sleeved on the outer wall of the main pole; a first spring is arranged inside the upper umbrella steel frame, and a support rod is connected to the end of the first spring; the lower umbrella steel frame is connected between the sliding block and the upper umbrella steel frame; the button is started, the hook pushes the spring leaf to be released, driving the third spring to be released, the U-shaped switch is released from the restriction, and the lever is corrected after the second spring is released from the initial compressed state; the sliding block moves downward under the action of the second spring, driving the lower umbrella steel frame to open the upper umbrella steel frame to a horizontal state, and the first spring is converted to a compressed state, and the support rod is tightly supported against the inner wall of the deformed section of the steel casing.

10. The complex karst geological rotary drilling and interlocking pile construction method according to claim 8 is characterized by: In the step three, when making the concrete loss prevention system in the karst area, firstly, a steel cage wrapped with an outer steel wire mesh is horizontally placed on a pedestal, and then a thin casing with an inner steel wire mesh is slid into the steel cage, and then the thin casing is pulled out, and the inner steel mesh, outer steel mesh and steel cage are connected together at the designed position with buckles.

Images