JPS6010014A - On-site piling work - Google Patents

Abstract

PURPOSE:To exactly place concrete to the bottom of a pit by a method in which an inverted conical form of a metal cover attached to the tip of a tremie tube is securely penetrated into the central soft portion of the bottom of the pit by the whole weights of the tremie tube and the concrete. CONSTITUTION:A pit 1 for driving a pile is excavated in the presence of mud water, and an iron bar cage 3 is inserted and set in the pit 1. An inverted conical form of a metal cover 4 is attached to the tip of a tremie tube 5, and the tremie tube 5 is inserted into the pit 1 until the metal cover 4 reaches through the slime 2 of the bottom to the bottom of the pit 1. Concrete is packed into the tremie tube 5, and the metal cover 4 is securely penetrated into the central soft ground of the bottom of the bit 1 by applying the whole weights of the tube 5 and the concrete C to the cover 4. The tremie tube 5 is then separated from the cover 4. Afterwards, while pulling up the tube 5 slowly, concrete C is poured into the pit 1 to form an on-site pile.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides the following steps: drilling a pile driving hole in the presence of a bentonite solution, inserting a reinforcing bar cage into the drilling hole, and inserting a tremie pipe into the drilling hole. It relates to a method for driving cast-in-place piles, which includes the step of inserting and installing concrete into a pile and pouring concrete therethrough.

Conventionally, this type of construction method has had the following problems.

That is, because a pile driving hole is excavated while injecting a large amount of a stabilizing liquid such as bentonite solution, a considerably thick layer of sediment, called slime, is formed at the bottom of the excavated hole. Ru. Therefore, before installing iron I11/I joints or pouring concrete, most of the slime is removed using the bottom cleaning packet method, air lift method, jet method, or jet lift method. Generally, it takes 3θ minutes to 3θ minutes to actually place concrete, so during this time slime will settle again at the bottom of the excavation hole, and in the end, a layer of slime of 3θan-gQtyn will remain. It ends up.

In addition, since the hole is usually excavated mechanically using an auger or the like, the bottom of the hole is weakened by the tip of the auger.

In this way, the bottom of the excavation hole becomes extremely soft due to the combination of slime sedimentation I11 and softening caused by machine scraping. First, after pouring concrete and building piles,
This tends to cause the pile to settle, especially if it settles unevenly.
There was a high possibility that there would be no adverse effect on the structure.

The present invention has been made in consideration of the above-mentioned conventional situation, and its purpose is to provide a completely new cast-in-place pile that can strengthen the soft layer at the bottom of an excavation hole and prevent the pile from sinking. The purpose is to provide a pouring method.

First, one embodiment of the present invention will be described below with reference to the drawings.

That is, the driving of cast-in-place piles according to the construction method of the present invention is performed in the following steps.

(1) First, as shown in Figure 1 (a), while injecting a stabilizing liquid (hole wall protection liquid) such as bentonite solution into a predetermined position, use an auger (not shown) etc. to drill into the pile driving hole. 1 is mechanically excavated and left for a certain period of time until the slime 2 settles at the bottom of the excavated hole 1.

(II) Next, as shown in FIG. 1(B), the ni1 precipitate slime 2 is removed by, for example, the packet construction method.

011) Then, as shown in FIG. 1(C), the front reinforcing bar 6 is inserted and installed.

Rei Next, the metal I of the inverted circular mongrel as shown in Figure 2! l!
! The lid 4 is attached to the tip of the tremie tube 5, and as shown in Fig. 1, the lid 4 (-J) is attached to the tremie tube 5. Insert until it penetrates and reaches the bottom of the borehole 1.

) In that state, as shown in Figure 1 (e), the tremie '+ #5 is filled with concrete C, and the tremie pipe 5 and the concrete C! J-) The entire weight of C is applied to the conical shell 4, and the cover 4 is inserted into the excavation hole 1.
Press it firmly into the soft center center of the bottom.

(a) Next, as shown in FIG. The tremie tube 5 and the lid body 4 are separated by the weight of the tremie tube 5 and the lid body 4.

&i) Thereafter, as shown in FIG. Pour concrete C continuously.

(An) Finally, as shown in FIG. 1(a), the excess concrete C' is removed and the ground G is leveled.

In addition, in the embodiment described in L, a metal inverted round mongrel was used as the lid 4 attached to the tip of the tremie tube 5, but other comparative materials such as one made of porcelain or hard porcelain were used. It may be made of a hard material, and it is not limited to an inverted conical shape, but may also be an inverted pyramid shape, or one with many sharp edges on the outer surface as shown in Figure 3 0) and (b). The protrusions 4a... may be added to form a reverse mongrel as a whole.

Further, as shown in FIG. 4, a protrusion 4C projecting in the diametrical direction is provided on the outer surface of the cylindrical shaft 4b fixed to the upper surface of the lid 4 of the inverted cone tube. A notch 5a is provided at the opening edge of 5 to fit in the vertical direction with the protrusion 4C, and by rotating the tremie tube 5 about its axis rsb, the lid 4 is rotationally driven. A spiral PK4d... is provided on the lower surface of the lid body 4 in a reverse circular shape.
The lid 4 may be screwed into the bottom of the excavation hole by lowering the tremie tube 5 while rotating it.

In summary, the method for driving cast-in-place piles according to the present invention is as follows:
The step of drilling a pile driving hole in the presence of muddy water, iron in the drilling hole →? a step of inserting and installing i1 Yu, and
In a construction method including a step of inserting and installing a tremie pipe into the excavation hole and pouring concrete through it, +'
When a tremie pipe is installed in an excavation hole and concrete is poured, an inverted conical cap is attached to the lower tip of the tremie pipe, and this inverted conical cap reaches the bottom of the excavation hole. The tremie pipe is inserted into the excavation hole, and in this state, the core tremie pipe is filled with concrete, and the entire weight of the tremie pipe and concrete is applied to the tip inverted conical lid. The method is characterized in that the tremie tube is lifted up a little to separate the tremie tube and the inverted conical lid due to the weight of the concrete, and then concrete is poured continuously while the tremie tube is gradually lifted up.

The functions and effects achieved by the above characteristic configuration are as follows.

That is, as shown in Fig. 1 (←) and (f) above, the bottom of the excavation hole is covered by the reverse cover attached to the tip of the tremie pipe, due to the total weight of the tremie pipe and the concrete inside it. It is possible to forcefully dig into the hole, and also to ensure that concrete is placed inside and around the lid, which functions similarly to cracked stone and sufficiently strengthens the soft layer at the bottom of the borehole. P1 As mentioned above, concrete can be reliably placed at the bottom of the excavation hole, so there is no slime layer remaining between the bottom of the hole and the lower end of the poured concrete pile, as in the conventional case. This has made it possible to reliably prevent damage to the superstructure due to subsequent pile settlement or uneven pile settlement.

[Brief explanation of the drawing]

Figures 1 to 8 show explanatory diagrams of embodiments of the construction method of the present invention, Figures 1 (a) to 1) are schematic sectional views showing the steps of the construction method, and Figure 2 is a perspective view of the main parts. FIGS. 3(A) and 3(B) are sectional views of the main parts of the respective embodiments. FIG. 4 is a perspective view of main parts showing another embodiment. 1... Pile driving hole, 2... Slime, 3... Steel cage, 4... Inverted conical lid, 5... Tremie pipe, C
···concrete. -2 Fig. 1 ('= ) (O) (No) (=) Fig. 2 j ” ” -'L,, -5 -J Fig. 3 (A) (B) Fig. 4 0

Claims (1)

[Claims] drilling a pile driving hole in the presence of muddy water; inserting and installing an iron 117i cage into the drilling hole; and
In a cast-in-place pile driving method that includes the step of inserting and installing a tremie pipe into the excavation hole and pouring concrete through it, installing the tremie tube into the excavation hole and pouring concrete, An inverted cone-shaped lid is attached to the lower tip of the tremie tube, and the tremie tube is inserted into the borehole until the inverted cone-shaped lid reaches the bottom of the borehole. filled with concrete,
The entire weight of the tremie pipe and concrete is applied to the tip of the inverted conical cap, and then the tremie pipe is pulled up slightly to separate the tremie pipe and the inverted conical cap by the weight of the concrete. A method of driving piles in places where concrete is poured in succession while gradually tightening the pipe.