JP3242356U - Composite pile foundation structure to fix the quicksand layer - Google Patents

Abstract

A composite pile foundation structure for anchoring a quicksand layer is provided. A composite pile foundation structure for fixing a quicksand layer of the present invention includes a quicksand layer, a support layer installed below the quicksand layer, a set of high-pressure jet agitation piles installed in the quicksand layer, drilled-in-place cast-in-place piles installed inside a set of high-pressure jet agitation piles. The high-pressure jet stirring pile is installed in a circle, and the bottom passes through the quicksand layer, effectively guaranteeing the fixing of the quicksand layer, and blocking the horizontal direction when driving the drilled cast-in-place pile. . When installing a drilling type cast-in-place pile, the present invention is designed so that the drilling type cast-in-place pile and the high-pressure injection stirring pile to be constructed overlap, so that the drilling type cast-in-place pile can be effectively implemented. and the combination of both can play the role of double reinforcement of the quicksand layer. [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention belongs to the technical field of drilled cast-in-place piles, and more particularly to a composite pile foundation structure for fixing a quicksand layer.

Pile foundation construction is the foundation and foundation of the entire construction, the quality of the pile foundation construction is related to the safety of the entire superstructure, and the progress of the pile foundation construction is related to the construction progress of the entire construction. In particular, there are many uncontrollable elements in the construction of a quicksand layer pile foundation, and how to quickly and efficiently handle the construction of a quicksand layer pile foundation is an issue in the construction industry. There are two main processing methods for conventional quicksand layer pile foundation construction as follows. 1) Adjusting the slurry solidified wall and adjusting the slurry solidified wall is currently the most common method in the processing of quicksand layer pile foundation construction. The adjustment improves the performance of the slurry hardening wall, thereby ensuring the stability of the pore wall as it passes through the quicksand layer. A common method is to pour pure clay or make a slurry with specific bentonite, 2) pass a long casing tube through the quicksand bed and use the long casing tube to direct the quicksand bed. The most direct method is to use the steel casing tube directly to hold and isolate the quicksand layer, and drive it directly into the steel casing tube when constructing the pile foundation. It is often used for soft quicksand layer geological features that are prone to collapse, and this method is applied to tip support piles.

However, both of these two types of methods have the following drawbacks. The first type is a slurry solidified wall treatment method, which makes holes smoothly, but tends to cause quality problems such as the holes collapsing during the installation of the reinforcing bar cage and the driving work, and the holes becoming excessively large. In the second type steel casing tube partitioning method, the steel plate is too smooth, so the friction pile lacks frictional force with this method, and eventually the load-bearing capacity of the pile foundation becomes insufficient. Cheap.

The present invention is a composite pile foundation structure and its construction to fix the quicksand layer in order to solve technical problems such as sand trapping in the quicksand layer, installation of high-pressure injection agitation piles, and driving of drilled-in-place piles. provide a way.

To achieve the above objectives, the present invention adopts the following technical solutions.
A composite pile foundation structure for fixing a quicksand layer, comprising a quicksand layer, a support layer installed below the quicksand layer, a set of high-pressure jet stirring piles installed in the quicksand layer, and a set of high-pressure jets. a drilled cast-in-place pile installed inside the agitation pile;
A set of high-pressure injection agitation piles are intermeshed and connected as a ring, a drilled-in-place cast-in-place pile is concentrically installed inside the ring, and an inner edge of the drilled-in-place cast-in-place pile and a set of high-pressure injection agitation piles. and overlap, the overlapping portion is a double pile laminate, the outer side of the double pile laminate is circular, the circle corresponds to the outer contour of the drilled-in-place pile,
The pile bottom of the high-pressure jet stirring pile passes through the quicksand layer and is embedded in the supporting layer, and the bottom of the drilling type cast-in-place pile is embedded in the supporting layer.

Further, the high-pressure injection agitation pile includes a front high-pressure injection agitation pile that is previously driven at intervals, and a rear high-pressure injection agitation pile that is connected to the front high-pressure injection agitation pile by meshing with the gap of the front high-pressure injection agitation pile.

Furthermore, the distance between the pile cores of the jet agitation piles is 450 mm or less, and the meshing thickness of the high-pressure jet agitation piles is 150 mm or more.

Further, the thickness of the double pile laminate is 150 mm or more, and the double pile laminate is provided with a rough surface or roughened surface.

Furthermore, the pile fixing area of the jet agitation pile is more than the value obtained by adding 1 m to the depth from the original ground to the lowest layer surface of the quicksand layer, and the quicksand layer at the bottom of the pile fixing area of the injection agitation pile is , without sand blasting from the bottom, the crushing strength of the injection stirring pile is not less than 0.5 MPa.

In addition, the double-pile laminate is further provided with connecting bars including vertical bars and horizontal bars spaced apart from the vertical bars, and the vertical bars and the horizontal bars form a square shape. , the connecting bar is pre-connected to the reinforcing bar cage of the cast-in-place pile.

Further, said drilled-in-place cast-in-place pile penetrates the support layer to form a fixed region of the cast-in-place pile body, and the bottom of the fixed region of the cast-in-place pile body is lower than the bottom of the fixed region of the jet agitation pile. .

Beneficial effects of the present invention are as follows.
1) The present invention uses high-pressure jet agitating piles, which are installed in a circle, and the bottom passes through the quicksand layer, effectively guaranteeing the fixing of the quicksand layer, and in the horizontal direction when the drilled cast-in-place pile is driven. occluded,
2) By installing the drilled-in-place pile, the present invention is useful for designing to stack the drilled-in-place pile and the high-pressure jet stirring pile to be constructed, and the effect of the drilled-in-place pile ensuring effective implementation, and the combination of both can serve as a double reinforcement of the quicksand layer,
3) The present invention is advantageous in effectively connecting the drilled-in-place cast-in-place pile and the high-pressure injection agitation pile through the installation of the connection reinforcing bar in the double pile stack.

Other features and advantages of the invention will be set forth in the ensuing content of the specification, and in part will become apparent in the specification, or may be learned by practice of the invention, and the principal objects and other advantages of the invention. can be realized and obtained by means of the solutions specifically pointed out in the specification.

It is the schematic of a drilling type cast-in-place pile and its connection structure. It is a structural schematic diagram of a drilled-in-place cast-in-place pile in a quicksand layer.

Taking a certain project as an example, in accordance with FIGS. A flow containing a support layer 9, a set of high-pressure injection agitating piles 2 installed in the quicksand layer 8, and a drilling type cast-in-place pile 1 installed inside the set of high-pressure injection agitating piles 2. Composite pile foundation structure is applied to fix the sand layer. A set of high-pressure injection agitation piles 2 are connected in a ring shape, and a drilled-in-place cast-in-place pile 1 is concentrically installed inside the ring, and the drilled-in-place cast-in-place pile 1 and a set of high-pressure injection agitation piles are concentrically installed. The inner edge of the pile 2 overlaps, and the overlapped portion is a double pile laminated portion 4, and the outer side of the double pile laminated portion 4 is circular, and the circular corresponds to the outer contour of the drilled-in-place pile 1. The bottom of the high-pressure jet stirring pile 2 passes through the quicksand layer 8 and is embedded in the support layer 9 , and the bottom of the drilled-in-place cast-in-place pile 1 is embedded in the support layer 9 .

In this embodiment, the diameter of the high-pressure injection agitating pile 2 is 600 mm, and in order to ensure sufficient strength and bearing capacity of the high-pressure injection agitating pile 2, the high-pressure injection agitating pile 2 is formed by drilling the cast-in-place pile 1 Start construction at least 7 days before construction. The drilled cast-in-place pile 1 is designed so that the size of the pile diameter is not limited, and can be applied to the drilled cast-in-place pile 1 of all diameters, and the drilling method can be percussion drilling, auger drilling, rotary drilling, etc. method can be adopted. The high-pressure injection agitating piles 2 were constructed using a high-pressure injection agitating pile driver, and the concrete manufacturing machine was P.I. O42.5 grade cement is used, the amount of cement used is 170 kg/m, that is, the amount of cement used is 600 kg or more for each cubic meter of reinforcing soil, and the water-cement ratio is 0.8 to 1.5. , an early strengthening agent is appropriately added, the 28d age strength is 0.8 MPa or more, and the pile length penetrates the quicksand layer 8 by 1 m or more.

In this embodiment, the high-pressure injection agitation piles 2 are the front high-pressure injection agitation piles 2 that are driven at intervals in advance, and the rear high-pressure injection agitation piles 2 that are connected by meshing with the gaps between the front high-pressure injection agitation piles 2. ,including. The distance 3 between the cores of the jet agitating piles is 450 mm or less, and the meshing thickness between the high-pressure jet agitating piles 2 is 150 mm or more. The fixed area 7 of the jet agitating pile is at least the value obtained by adding 1 m to the depth from the original ground to the lowest layer surface of the quicksand layer 8, and the quicksand layer 8 at the lower end of the fixed area 7 of the jet agitating pile is , without sand blasting from the bottom, the crushing strength of the injection stirring pile is not less than 0.5 MPa.

In this embodiment, the thickness of the double-pile laminate 4 is more than 150 mm, and the double-pile laminate 4 is provided with a rough surface or roughened surface. The double-pile laminated part 4 is further provided with connecting bars including vertical bars and horizontal bars that are spaced apart from the vertical bars. The reinforcement is pre-connected to the reinforcing bar cage of the drilled cast-in-place pile 1 .

In this embodiment, the drilled cast-in-place pile 1 penetrates the support layer 9 to form a fixed area 6 of the cast-in-place pile body, and the bottom of the fixed area 6 of the cast-in-place pile body is the fixed area of the jet agitation pile. lower than the bottom of region 7;

1 and 2, the construction method of the composite pile foundation structure fixing the quicksand layer is further described, and the specific steps are as follows.

In step 1, the thickness of the stratum of the quicksand layer 8 is explored, the distribution of the quicksand layer 8 and the soil layer distribution under the quicksand layer 8 are clarified by underground radar or drilling exploration technology, and the bottom of the quicksand layer 8 determine the position and thickness of the support layer 9 of .

In step 2, the position of the high-pressure injection agitation pile 2 is determined based on the diameter of the drilled-in-place pile 1 to be constructed, and here, by setting the thickness of the double pile laminated part 4, The point of each high-pressure jet agitating peg 2 is reverse estimated.

In step 3, at the time of site construction, the high-pressure injection agitating piles 2 are driven in at intervals of the holes, the front high-pressure injection agitating piles 2 are driven first, and then the front high-pressure injection agitating piles 2 have the design strength. After satisfying the vertical requirements, the post high-pressure jet stirring pile 2 is driven, the front high pressure jet stirring pile 2 and the post high pressure jet stirring pile 2 are meshed and connected, and the mesh thickness is 150 mm or more.

In step 4, a ring-shaped reinforcing cylindrical region is formed for the high-pressure injection agitation pile 2, and the bottom of the high-pressure injection agitation pile 2 is passed through the quicksand layer 8 and penetrated into the support layer 9, whereby the high-pressure injection agitation pile 2 to form a ring-shaped pile fixing area 7 of the injection churning pile, the pile fixing area 7 of the injection churning pile blocks the inflow of the quicksand layer 8, and the inside of the pile fixing area 7 of the injection churning pile is drilled. The cast-in-place pile 1 is constructed, and the high-pressure injection agitating pile 2 is constructed at least seven days before construction of the drilled-in-place pile 1.

In step 5, a double pile laminate 4 is installed between the drilled-in-place pile 1 and the high-pressure injection agitation pile 2, and the inside of the high-pressure injection agitation pile 2 is cut to form a circular outline, and this A circular outline adapts to the drilled-in-place cast-in-place pile 1 to be constructed.

In step 6, drilling pile holes 5 necessary for drilling piles 1 are driven by cutting equipment and drilling installation, and then drilling piles 1 are drilled into pile holes 5. , and the bottom of the drilled-in-place pile 1 penetrates into the support layer 9 and is lower than the high-pressure injection stirring pile 2, so that the drilled-in-place cast-in-place pile 1 in the quicksand layer 8 complete the construction of

In this embodiment, the vertical plane of the double pile laminate 4 is set as an uneven surface by roughening or drilling in the cutting process, and then tightly and integrally fixed with the drilled-in-place pile 1. make a connection. After the drilling type cast-in-place pile 1 is completed, in the double pile laminated part 4, a connecting reinforcing bar is further installed correspondingly to the cut gap part, and the connecting reinforcing bar is made into a "?" shape. is arranged and attached together with the reinforcing bar cage of the drilled-in-place pile 1.

What has been described above is only the preferred and specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. should be included in the protection scope of the present invention.

1... drilling type cast-in-place pile, 2... high-pressure injection agitating pile, 3... distance between the center of the injection agitating pile, 4... double pile lamination part, 5... drilling pile hole, 6... fixation of cast-in-place pile body Area, 7... Fixed area of injection stirring pile, 8... Quicksand layer, 9... Support layer

Claims (6)

A quicksand layer (8), a support layer (9) installed below the quicksand layer (8), a set of high-pressure jet stirring piles (2) installed in the quicksand layer (8), and a set of A drilled-in-place cast-in-place pile (1) installed inside the high-pressure injection agitation pile (2),
A set of high-pressure injection agitation piles (2) are connected in an annular shape, and a drilled-in-place pile (1) is concentrically installed inside the annular shape, and the drilled-in-place cast-in-place pile (1) and The inner edge of a set of high-pressure injection agitating piles (2) overlaps, the overlapping part is the double pile laminated part (4), the outer side of the double pile laminated part (4) is circular, and the circle is A composite pile foundation structure for anchoring a quicksand layer corresponding to the outer contour of a drilled cast-in-place pile (1), characterized in that. The pile bottom of the high-pressure injection stirring pile (2) passes through the quicksand layer (8) and is embedded in the support layer (9), and the bottom of the drilled-in-place pile (1) is embedded in the support layer (9). The composite pile foundation structure for fixing a quicksand layer according to claim 1, characterized in that it is embedded. The high-pressure injection agitating pile (2) is a front high-pressure injection agitating pile (2) that is driven in advance at intervals, and a rear high-pressure injection agitating pile (2) that is connected by meshing with a gap between the front high-pressure injection agitating pile (2). The composite pile foundation structure for fixing a quicksand layer according to claim 1, characterized by comprising: 2. The method according to claim 1, characterized in that the thickness of the double pile laminate (4) is greater than or equal to 150mm, and the double pile laminate (4) is provided with a rough surface or roughened surface. Composite pile foundation structure to fix the quicksand layer. Said double-pile laminate (4) is further provided with connecting bars comprising vertical bars and horizontal bars spaced from the vertical bars, the vertical bars and horizontal bars forming a "?" shape. The composite pile foundation structure for anchoring the quicksand layer according to claim 1, characterized in that the connection bars are pre-connected to the reinforcing bar cage of the drilled cast-in-place pile (1). Said cast-in-place pile (1) penetrates into the support layer (9) to form a fixed area (6) of the cast-in-place pile body, and the bottom of the fixed area (6) of the cast-in-place pile body is Composite pile foundation structure for anchoring a quicksand layer according to claim 1, characterized in that it is lower than the bottom of the anchoring area (7) of the stirring pile.

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