Prefabricated piles and methods of use thereof

Abstract

The present invention discloses a prefabricated pile, comprising: a prefabricated pile body, a plurality of side grooves opened on the walls around the pile body of the prefabricated pile body along the direction of pile sinking, and a water-permeable filler filled into the side grooves; the side grooves start from the bottom of the pile body of the prefabricated pile body to the bottom of the conical pile tip of the prefabricated pile body; when sinking the pile, the water-permeable filler gradually fills into the side grooves as the prefabricated pile body sinks. The present invention opens a plurality of side grooves around the pile body of the original prefabricated pile, and uses dry yellow sand, permeable concrete and other permeable fillers to fill the side grooves during the pile sinking process, and discharges water in the soil on the side of the pile through the permeability of the permeable filler, thereby reducing the excess pore water pressure.

Description

Technical Field

[0001] The invention relates to a prefabricated pile, in particular to a prefabricated pile with a self-draining function used for a saturated soft clay foundation, and belongs to the technical field of civil engineering. Background Art

[0002] The foundations in soft soil areas such as coastal areas have the characteristics of high water content, high compressibility, and poor permeability. When prefabricated piles and other squeeze piles are constructed on such foundations, the soil on the pile side is squeezed, disturbed, and reshaped by the pile body drilling into it, which is prone to produce excess pore water pressure. This excess pore water pressure, such as Fig.10 As shown, the piles constructed later are likely to cause the foundation soil to bulge and squeeze horizontally, resulting in the displacement, "floating piles", and tilt of the constructed piles, making it difficult to ensure the quality of pile driving construction, and may have a serious impact on the surrounding environment and easily cause engineering accidents.

[0003] The existing solutions to the above problems are as follows: 1. Before sinking piles, set sand wells, sand bag wells, plastic drainage boards or crushed stone piles outside the pile position to eliminate part of the excess pore water pressure. 2. Dewater the well points so that the pile foundation does not generate excess pore water pressure within a certain depth range. 3. Control the pile driving speed or the number of piles sunk per day to facilitate the release of excess pore water pressure. 4. Use pre-drilling methods to reduce the soil squeezing effect. 5. Use reasonable pile driving routes and sequences to increase the interval time between piles at the same location, which is conducive to the release of excess pore water pressure. 6. Set up isolation steel sheet piles, underground continuous walls or pile row type rotary jet piles to limit the soil squeezing phenomenon of pile sinking. 7. Set up stress release holes to reduce pore water pressure and guide the soil squeezing trend.

[0004] Although the existing methods can reduce the impact of the soil squeezing effect during the precast pile sinking process, they increase the construction links, energy consumption and construction costs of the precast piles, and extend the construction period to a certain extent. Summary of the invention

[0005] The purpose of the present invention is to provide a precast pile and a method for using the same, so as to solve the technical defects of increasing the construction links of the precast pile, energy consumption, construction cost and extended construction period when preventing excess pore water pressure when sinking piles in saturated soft clay foundation.

[0006] A precast pile comprises: a precast pile body, a plurality of side grooves opened on the walls around the precast pile body along the direction of pile sinking, and a water-permeable filler filled in the side grooves; the side grooves start from the bottom of the precast pile body to the bottom of the conical pile tip of the precast pile body; when the pile is sunk, the water-permeable filler is gradually filled into the side grooves as the precast pile body sinks.

[0007] Furthermore, the prefabricated pile also includes several rope buckles and several guide ropes; the rope buckle is arranged in the groove of the side groove at one end of the pile tip; the guide rope passes through the side groove, one end is connected to the rope buckle, and the other end extends out of the side groove.

[0008] Furthermore, a plurality of the rope buckles and a plurality of guide ropes are arranged in one of the side grooves.

[0009] Furthermore, the slot width A of the side slot is less than or equal to the slot inner width B of the side slot.

[0010] Furthermore, the side groove is dovetail-shaped.

[0011] Furthermore, the water-permeable filler is dry yellow sand or a mixture of dry yellow sand and fast-setting material.

[0012] Furthermore, the permeable filler is permeable concrete.

[0013] A method for using prefabricated piles, the specific steps are as follows:

[0014] Step 1: Sink the prefabricated piles at the pile positions;

[0015] Step 2: Place permeable filler in the sand filling funnel, and use the sand filling funnel to fill the permeable filler into several side grooves of the prefabricated piles until the pile sinking is completed.

[0016] Furthermore, before step 1, the method further includes: inserting the guide rope into the side groove, and connecting one end of the guide rope to the rope buckle.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention opens several side grooves around the pile body of the original prefabricated pile, and fills the side grooves with permeable fillers such as dry yellow sand and permeable concrete during the pile sinking process. The water in the soil on the side of the pile is discharged through the permeability of the permeable fillers, thereby reducing the excess pore water pressure.

[0019] The guide rope can play a role in driving the permeable filling material in the side ditch during the pile sinking process, thereby preventing the permeable filling material from being unable to continue sinking along the side ditch when encountering groundwater.

[0020] The side groove opening width is made smaller than the side groove inner width to prevent part of the permeable dry yellow sand from being retained in the soil layer when the precast piles sink below the groundwater level due to the viscosity of the sand in the side groove being greater than the viscosity between the sand particles. This results in less yellow sand in the side groove as the piles sink deeper. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of pile sinking without a guide rope according to the present invention;

[0022] Figure 2This is a schematic diagram of pile sinking with a guide rope according to the present invention;

[0023] Figure 3 It is a partial enlarged view of the present invention without a guide rope;

[0024] Figure 4 It is a partial enlarged view of the present invention when there is a guide rope;

[0025] Figure 5 The side groove of the present invention is a cross-sectional view of “▽”;

[0026] Figure 6 is a cross-sectional view of a dovetail-shaped side groove of the present invention;

[0027] Figure 7 The side groove of the present invention is a rectangular cross-sectional view;

[0028] Figure 8 is a cross-sectional view of the side groove of the present invention with a guide rope;

[0029] Fig. 9 It is a cross-sectional view at CC of the present invention;

[0030] Fig.10 This is a schematic diagram of soil squeezing during construction;

[0031] Fig.11 It is the experimental data curve diagram of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0033] like Figure 1-9 As shown, the prefabricated pile of the present invention is used for sinking piles on saturated soft clay foundation, comprising: a prefabricated pile body 1, a plurality of side grooves 2 opened on the walls around the pile body 6 of the prefabricated pile body 1 along the direction of sinking pile, and a water-permeable filler 3 filled into the side grooves 2; the side grooves 2 start from the bottom of the pile body 6 of the prefabricated pile body 1 to the bottom of the conical pile tip 7 of the prefabricated pile body 1; when sinking the pile, the water-permeable filler 3 is filled into the side grooves 2 to form a water-permeable well in the side grooves 2, such as Fig. 9 As shown, the moisture in the side soil around the prefabricated pile body 1 will be discharged from the permeable well formed by the permeable filling material 3 in the side groove 2.

[0034] Take the pile body 6 of the prefabricated pile body 1 as an example, which is a square prism. Figure 5 As shown, a "▽"-shaped side groove 2 is opened on the four sides of the pile body 6; the most preferred shape of the side groove 2 is a side groove 2 whose groove width A is less than or equal to the groove width B of the side groove 2. The shape of the side groove 2 can be as follows Figure 6 As shown, the dovetail shape provided on the four sides of the pile body 6 can also be as shown in FIG. Figure 7As shown, the rectangular parallelepiped opened on the four sides of the pile body 6, when filling the permeable filler 3 into the side groove 2, if the groove width A of the side groove 2 is greater than the groove width B, the pressure or viscosity in the side groove 2 will be greater than the friction between the sand and the sand, and between the sand and the pile body 6 due to the squeezing of the side soil, and the permeable filler 3 will not be filled smoothly. When the groove width is less than or equal to the groove width, the pressure or viscosity in the side groove 2 will not be greater than the friction between the sand and the sand, and between the sand and the pile body 6, so that a good permeable well can be formed in the side groove 2.

[0035] Even if the optimal shape of the side groove 2 is used, filling may still be obstructed when encountering groundwater. When making the prefabricated pile body 1, one or more rope buckles 4 can be prefabricated at one end of the pile tip 7 of the side groove 2. The front and back, up and down positions of the rope buckles 4 can be reasonably distributed according to the actual shape of the side groove 2, and one or more guide ropes 5 are tied to the rope buckles 4. The guide ropes 5 pass through the side groove 2. During the pile sinking process, the guide ropes 5 will sink with the prefabricated pile body 1 and carry the permeable filler 3 into the side groove 2. When encountering groundwater, the traction and blocking effect of the guide ropes 5 reduces the influence of groundwater on the downward filling of the permeable filler 3 in the side groove 2.

[0036] The permeable filler 3 can be made of dry yellow sand or a mixture of dry yellow sand and fast-setting materials or permeable concrete, as long as it can play a permeable role. When using a mixture of dry yellow sand and fast-setting materials, since the fast-setting materials will only solidify when they meet water, they can be poured into the side groove 2 together with the dry yellow sand during filling. When the fast-setting materials meet water, they solidify. The solidified fast-setting materials will have a certain strength and have a certain adhesion with the groove wall of the side groove 2, which can ensure the continuity of the dry yellow sand in the side groove 2. At this time, the places with fast-setting materials will harden, and the places without fast-setting materials will still be loose dry yellow sand, ensuring that the dry yellow sand in the side groove 2 is loose and not scattered. When the permeable filler 3 is a permeable concrete such as sandless concrete, the permeable concrete can be pre-cast in the side groove 2 when the prefabricated pile body 1 is made, so that the permeable concrete is directly formed in the side groove 2, and then settled with the prefabricated pile body 1. The gaps in the permeable concrete form waterways to play a drainage role.

[0037] When using, Figure 1 As shown, a sand filling funnel can be pre-set at the pile position of the precast pile of the technical solution, and a water-permeable filler 3 is pre-set in the sand filling funnel. When the precast pile is sunk, the sand filling funnel is aligned with the side groove 2, and the water-permeable filler 3 is poured into the side groove 2. Fig. 9 As shown, the water-permeable filler 3 will fill the side groove 2. Figure 2 As shown, when sinking piles, while the sand filling funnel fills the water-permeable filler 3 into the side groove 2, the guide rope 5 outside the side groove 2 will also pull the water-permeable filler 3 into the side groove 2, and the guide rope 5 inside the side groove 2 will pull the water-permeable filler 3 to continue moving downward to avoid blockage.

[0038] like Fig.11 As shown in the figure, the experimental environment adopts the field test method. At 4 hours, the precast piles with side groove 2 have released more than 50% of the excess pore water pressure, while the ordinary precast piles have increased the excess pore water pressure at 2 hours. Until 48 hours, the precast piles with side groove 2 have almost completely released the excess pore water pressure, while the ordinary precast piles have only released about 10%.

[0039] In terms of economy, the cost of reducing excess pore water pressure through sand wells in the existing technical solutions is relatively low compared to other solutions. The sand well solution requires the use of prefabricated piles and sand piles. Taking the use of 200 prefabricated piles with a length of 10m and 200 sand piles with a length of 10m and a pile diameter of 100mm to reduce excess pore water pressure as an example, the cost calculation is calculated according to the existing relevant price and cost regulations. Table 1 is the sand pile construction fee (including materials), and Table 2 is the machinery entry (exit) and assembly and disassembly fee. The two costs total 34,971 yuan; through this technical solution, only prefabricated piles with side grooves 2 are needed. Taking the use of 200 prefabricated piles with a length of 10m and side grooves 2 to reduce excess pore water pressure as an example, the cost calculation is calculated according to the existing relevant price and cost regulations, and the total cost is 5,439 yuan. It can be seen from the three data tables that the use of prefabricated piles with side grooves 2, that is, the prefabricated piles provided by this technical solution, can be nearly 5.4 times lower in cost than the cost of the existing technical solution.

[0040] Labor cost Material cost Machinery Fee Management Fee profit Tax regulations taxes total 1660 5400 2480 460 280 185 423 10888

[0041] Table 1

[0042]

[0043] Table 2

[0044] Labor cost Material cost Machinery Fee Management Fee profit Tax regulations taxes total 1000 2763 1000 250 150 84 192 5439

[0045] Table 3

[0046] At the same time, the pile driving method provided by the present technical solution replaces the method of completing pile driving on a saturated soft clay foundation in multiple construction stages in the prior art by filling the side groove 2 with a permeable filler 3 during the pile driving process or prefabricating the permeable filler 3 in the side groove 2 when making prefabricated piles, thereby shortening the construction period and reducing the consumption of construction resources.

[0047] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present invention.

Claims

1. A prefabricated pile, characterized in that: include: A prefabricated pile body, several side grooves opened on the walls around the pile body of the prefabricated pile body along the direction of pile sinking, and permeable fillers, several rope buckles and several guide ropes filled in the side grooves, wherein the permeable filler is dry yellow sand or a mixture of dry yellow sand and fast-setting material; the side grooves start from the bottom of the pile body of the prefabricated pile body to the bottom of the conical pile tip of the prefabricated pile body; when sinking the pile, the permeable filler is gradually filled into the side groove as the prefabricated pile body sinks; the rope buckle is arranged in the groove of the side groove at one end of the pile tip; the guide rope penetrates into the side groove, one end is connected to the rope buckle, and the other end extends out of the side groove, and several rope buckles and several guide ropes are arranged in one side groove; the groove width A of the side groove is less than or equal to the groove width B of the side groove, forming a dovetail shape.

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