Double-row pile front-back row underground pulling-pressing connecting device
By connecting the steel barrel of the rear pile in the double row pile structure with the tensioning device of the front pile, the steel pressing rod is used to transmit the load, which solves the problem that the double row piles are difficult to allocate soil pressure load under weak geological conditions. Better soil adaptability and stress coordination are achieved.
Patent Information
- Application Number
- CN202421211314.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-29
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-05-29
AI Technical Summary
Under weak geological conditions, it is difficult for double-row piles to effectively allocate soil pressure loads, resulting in displacement and failure of the support system.
The double-row pile front and rear rows of the bottom pull-pressure connection device is used to connect the steel cylinder of the rear row pile to the pull-pressure device of the front row pile, and the load is transmitted by the steel press rod, and the bending resistance is improved through the cone-shaped fit and anchor structure. , shear performance.
It has achieved better adaptation to the properties of the soil, reasonably allocated the stress of the front and rear piles, and coordinated distribution of soil pressure, which has improved the stiffness and gravity stability of the soil between the double piles.
Smart Images
Figure CN222435299U_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an underground tension-compression connection device for front and rear rows of double-row piles, belonging to the field of water conservancy. Background Art
[0002] In water conservancy, water transport, hydropower and other projects, the double-row pile structure has a good supporting effect. Combined with high-pressure jet grouting and ground-connected walls, it can solve the functions of support and anti-seepage. It is widely used in foundation pit projects and retaining and protection projects. Due to soft geological conditions such as silt, it is difficult for the front and rear rows of piles to distribute the soil pressure load well, resulting in large displacement of the support system and failure.
[0003] Before excavation, both rows of piles are located in the soil, and there is no possibility to add front and rear rows to connect; after excavation, the front row of piles is gradually exposed, but the rear row of piles is still located in the soil, and it is still impossible to implement the front and rear row of piles connection. Understanding of the joint action mechanism of double-row piles and soil, especially the separate action of front and rear rows of piles. (1) Double-row pile rigid frame model, the soil pressure behind the front row of piles is distributed according to the proportion of the soil weight on the sliding surface between piles; (2) Considering the bending stiffness of the soil between piles, a third-row pile auxiliary model is proposed, and the soil pressure is redistributed according to the proportional coefficient. This model further improves the rationality of the displacement calculation of soft soil foundation pit. (3) For the anti-sliding effect of double-row piles, there are two types of soil arch effects (end-bearing arch and friction arch) with ultimate bearing capacity. When the double-row piles are subjected to different landslide thrusts, the distribution law of the soil resistance between piles and in front of the piles is that the spacing between the piles should be greater than the "rise height + half arch thickness" of the end-bearing arch of the front row of piles.
[0004] Existing anchor retaining structures, multi-layer connected double-row piles, and double-row pile structures with anchor rods have limitations. For example, in the anchor retaining structure, the front row is a retaining structure, and the rear row can only provide reliable horizontal force to the top of the front row piles (plates), but cannot provide horizontal force to the front row piles (plates). This puts forward high requirements on the bending and shearing capacity of the front row piles, increases the engineering cost, and reduces the applicability of the structure; based on the idea of vertically turning the rear to horizontally jacking the prestressed tendons, the front triangular steel sheet piles actively accept the prestressed tendons, which has pioneered research in this area, but has low operability and only stays in the tension force mode, and cannot apply sufficient pre-tension and compressive stress to improve the integrity; anchor cable reinforcement is implemented for the pile body of double-row piles and single-row pile structures, which is an efficient method, but is limited by geological conditions, underground space, inclination angle, and application efficiency. Summary of the invention
[0005] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an underground tension-compression connection device for the front and rear rows of double-row piles, which can better adapt to the properties of the soil, better and more reasonably distribute the forces on the front and rear rows of piles, and distribute the soil pressure through the relative cooperation of the displacement of the front and rear rows of piles. When the soil is soft and the soil arch effect cannot be formed, most of the soil pressure acts on the front row of piles, and the tension rod plays a role at this time; when the load on the rear row of piles is too large, the load can be transferred to the front row of piles through the rigid compression rod.
[0006] Technical solution: To solve the above technical problems, the present invention provides an underground tension-compression connection device for the front and rear rows of double-row piles, wherein the lower end of the rear row piles is a concrete pile, and the upper end is a steel cylinder, the steel cylinder is sleeved on the concrete piles at the lower end, the steel cylinder is connected to the front row piles through a tension-compression device, and the top of the steel cylinder and the top of the front row piles are connected through a connecting plate; the inner wall of the lower end of the steel cylinder is provided with a frustum hole, the top of the concrete pile of the rear row piles is frustum-shaped, and the maximum diameter of the top of the concrete pile is 0.9-0.95 times the concrete column diameter of the rear row piles, and the concrete piles of the rear row piles are connected to the steel cylinder through a frustum-shaped fit.
[0007] Preferably, the tension and compression device comprises a purlin and a connecting rod, the purlin is located on one side of the front row of piles, and the connecting rod is connected to the purlin and the steel cylinder through an anchor.
[0008] Preferably, the connecting rod is a pair, and is connected to the purlin and the steel tube at the same time through the pair of connecting rods.
[0009] Preferably, at least two groups of the tension and compression devices are arranged along the vertical direction.
[0010] Preferably, the purlin is a steel purlin, the lower part of the front row piles is a concrete pile, and the upper part is a steel cylinder, and the steel purlin is anchored to the steel cylinder of each front row pile.
[0011] Preferably, the length of the steel cylinder of the rear row piles located in the concrete is 2-3 times the diameter of the concrete of the rear row piles.
[0012] Preferably, the top of the lower concrete pile of the rear row pile is connected to the front row pile by an anchor rod, and the angle between the anchor rod and the rear row pile is 30-60°. The anchor rod is anchored near or below the foundation surface of the rear row pile. Since the displacement of the pile body below the foundation surface is relatively small, it can bear a higher horizontal force, which solves the problem of being unable to achieve a reliable anchor point at the rear under complex conditions. The oblique anchoring is more efficient than the horizontal anchoring rod.
[0013] As a preference, the rear row of steel cylinders are replaced with prefabricated reinforced concrete pipe piles, caissons, etc.
[0014] In the present invention, the front row piles remain unchanged, and the original general steel casing of the rear row piles is changed into a steel cylinder of designed length, and the steel cylinder body is provided with receiving holes and water collection holes; the lower part of the rear row piles is constructed in the same manner as the general cast-in-place piles, which is called the first-phase concrete, and the first-phase concrete enters twice the diameter of the steel cylinder pile; the steel cage is extended to the ground, which is consistent with the general piles; after the pile body concrete is finally set, the mud and water in the steel cylinder are extracted, and necessary cleaning is carried out; the floating slurry on the pile top is removed; according to the bending resistance requirements of the pile body, part of the steel bars are welded to the steel cylinder; as the excavation is carried out, the jacking or drilling equipment is used for directional construction on the foundation pit surface after excavation, High-strength prestressed tendon tension rod materials and circular or rectangular cross-section steel pipes are delivered to the receiving hole position; the prestressed tendons can be arranged inside or outside the steel pipe. In addition, the steel pipe itself can be subjected to both tension and compression at the same time. Concrete or mortar materials can be poured into the steel pipe to improve stiffness and reliability; for rods that only consider tension, only prestressing can be implemented, and springs can be placed under the anchor plate to alleviate the influence of deformation; for rods that are also subject to pressure, the rods and purlins need to be anchored on the front row of piles and the rear row of steel cylinders. The front row of piles can make full use of the reinforcement of the pile body, and the rear row can make use of the cylinder body.
[0015] Beneficial effect: The underground tension-compression connection device of the front and rear rows of double-row piles of the present invention can better adapt to the properties of soil, better and more reasonably distribute the forces on the front and rear rows of piles, and distribute the soil pressure through the relative cooperation of the displacement of the front and rear rows of piles. When the soil is soft and the soil arch effect cannot be formed, most of the soil pressure acts on the front row of piles. At this time, the pull rod plays a role, so that part of the load is transferred to the rear row of piles, so that the rear row of piles and the front row are coordinated in force, and the stiffness and gravity stabilization of the soil between the double-row piles are better played; the rear row of piles are divided into upper and lower partitions by steel cylinders to improve the overall bending and shearing properties, and tension and compression rods are arranged in the area to improve the bending resistance of local connections. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a front view schematic diagram of the present invention.
[0017] Figure 2 It is a schematic diagram of the top structure of the present invention.
[0018] Figure 3 Another structural schematic diagram of the present invention.
[0019] Figure 4 It is a schematic diagram of the connection of the rear row piles of the present invention. DETAILED DESCRIPTION
[0020] The present invention will be further described below in conjunction with the accompanying drawings.
[0021] like Figures 1 to 4As shown, a double-row pile front and rear row underground tension-compression connection device of the present invention comprises a front row pile 3 and a rear row pile 5, wherein the front row pile 3 is a concrete pile, the lower end of the rear row pile 5 is a concrete pile 4, and the upper end is a steel cylinder 1, the steel cylinder 1 is sleeved on the concrete pile at the lower end, the steel cylinder is connected to the front row pile 3 through a tension-compression device, and the top of the steel cylinder is connected to the top of the front row pile 3 through a connecting plate. The length of the steel cylinder of the rear row pile 5 located in the concrete is 2-3 times the diameter of the concrete of the rear row pile 5; the inner wall of the lower end of the steel cylinder is provided with a frustum hole, the top of the concrete pile of the rear row pile is frustum-shaped, and the maximum diameter of the top of the concrete pile is 0.9-0.95 times the diameter of the concrete column of the rear row pile, the steel cylinder is supported by a step, and the concrete pile of the rear row pile is connected to the steel cylinder by a frustum-shaped cooperation. Through the frustum-shaped step, the steel cylinder can be quickly pressed on the concrete pile of the rear row pile.
[0022] like Figure 2 As shown, the tension and compression device comprises a purlin 6 and a connecting rod 2. The purlin 6 is located on one side of the front row of piles 3. The connecting rod 2 is connected to the purlin 6 and the steel cylinder through an anchor. The connecting rod 2 is a pair, and the purlin 6 and the steel cylinder are connected at the same time through a pair of connecting rods 2. The tension and compression device is provided with at least two groups in the vertical direction.
[0023] like Figure 3 As shown, the purlin 6 is a steel purlin 6, the lower part of the front pile 3 is a concrete pile, and the upper part is a steel cylinder, and the steel purlin 6 is anchored to the steel cylinder of each front pile 3. The connecting rod 2 can be connected at an angle to better play the anchoring role and improve the overall performance.
[0024] In the present invention, in addition to the soil retaining function, the double-row piles can also be used to build buildings on the upper part, such as the lock chamber of the ship lock, the retaining wall of the pilot channel, etc., and the front and rear rows of piles 5 of the double-row piles can be used to share the soil pressure through the working well, which plays the role of anchoring. Among them, the lower normal cast-in-place piles and the upper steel cylinder still conform to the traditional process habits, and their functions are greatly expanded, from the original casing to the working well. The steel cylinder is expanded into a working well, and a receiving hole or receiving window is set on the wall of the working well. The present invention better adapts to the properties of the soil, better and more reasonably distributes the force of the front and rear rows of piles 5, and distributes the soil pressure through the relative cooperation of the displacement of the front and rear rows of piles 5. When the soil is soft and the soil arch effect force is not formed, most of the soil pressure acts on the front row of piles 3. At this time, the pull rod plays a role, so that the load is partially transferred to the rear row of piles 5, so that the rear row of piles 5 and the front row are coordinated to bear force, so as to better play the rigidity effect of the soil between the double-row piles and the gravity stabilization effect.
[0025] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. A double-row pile front and rear row underground tension-compression connection device, comprising front row piles and rear row piles, wherein the front row piles are concrete piles, characterized in that: The lower end of the rear row pile is a concrete pile, and the upper end is a steel cylinder. The steel cylinder is sleeved on the concrete pile at the lower end, and the steel cylinder is connected to the front row piles through a tension and compression device. The top of the steel cylinder and the top of the front row piles are connected through a connecting plate; the inner wall of the lower end of the steel cylinder is provided with a frustum hole, and the top of the concrete pile of the rear row pile is frustum-shaped. The maximum diameter of the top of the concrete pile is 0.9-0.95 times the concrete column diameter of the rear row pile, and the concrete pile of the rear row pile is connected to the steel cylinder through a frustum-shaped fit.
2. The underground pull-compression connection device for the front and rear rows of double-row piles according to claim 1 is characterized in that: The tension and compression device comprises a purlin and a connecting rod, wherein the purlin is located at one side of the front row of piles, and the connecting rod is connected to the purlin and the steel cylinder through an anchor.
3. The underground pull-compression connection device for the front and rear rows of double-row piles according to claim 2 is characterized in that: The connecting rods are a pair, and are connected to the surrounding purlin and the steel tube at the same time through the pair of connecting rods.
4. The underground pull-compression connection device for the front and rear rows of double-row piles according to claim 2 or 3, characterized in that: At least two groups of the tension and compression devices are arranged along the vertical direction.
5. The underground pull-compression connection device for front and rear rows of double-row piles according to claim 2 is characterized in that: The purlin is a steel purlin, the lower part of the front row piles is a concrete pile, and the upper part is a steel cylinder, and the steel purlin is anchored to the steel cylinder of each front row pile.
6. The underground pull-compression connection device for the front and rear rows of double-row piles according to claim 1, characterized in that: The length of the steel cylinder of the rear row piles located in the concrete is 2-3 times the diameter of the concrete of the rear row piles.
7. The underground pull-compression connection device for front and rear rows of double-row piles according to claim 1, characterized in that: The top of the lower end concrete pile of the rear row pile is connected to the front row pile through an anchor rod, and the angle between the anchor rod and the rear row pile is 30-60 degrees.