JPS58173220A - Construction of foundation pile - Google Patents

Abstract

PURPOSE:To exactly form a friction cut part by a method in which iron bars and a thin inner tube are erected in a casing set underground and then concrete is placed into the inner tube to construct the upper part of a pile. CONSTITUTION:After or while excavating a shaft A in the ground, a casing 1 is erected in the ground, and an iron bar cage 2 is inserted into the casing 1. Then, a inner tube 4 with a thin wall of a corrugated pipe, etc., whose tip part is wound with a strap packing 3 of an expanded synthetic resin, e.g., urethane form, is erected on the inside of the casing 1 and on the outside of the iron bar cage 2. Then, ready-mixed concrete 5 is placed into the shaft A until it reaches the bottom of the casing 1 and then the casing 1 is slightly pulled up in such a way as to prevent the extension of the concrete 5 to the outside of the inner tube 4.

Description

[Detailed Description of the Invention] This invention relates to a method for constructing cast-in-place foundation piles.
The purpose is to prevent the generation of frictional force between the upper part of the pile and the soil in the O-loading test of cast-in-place piles.

The bearing capacity of foundation piles is measured by carrying out a loading test on the required piles driven in.
1 on the desk because it will be cut after rounding the ground excavation for basement floor construction.
1 requires that the foundation pile be constructed so that a loading test can be carried out without any frictional force acting on it.

In order to meet the above-mentioned needs, the present invention has developed a method that can be implemented economically.The details of the S+ will be explained below with reference to the drawings and nine embodiments.

First, after drilling a hole in the ground, or without digging, the casing 1 is pushed into the ground to a required depth of at least 7 holes. Next, the reinforcing bar cage 2 is inserted into the cooling cage 1. In addition, the cap tire and tip of the rebar gauge.

All the intermediate sinking needles are attached inside the reinforcing bar cage 2 (not shown).Next, a belt-shaped banking 3 made of foamed synthetic resin such as foamed urethane is wrapped around the outer circumference of the tip, and a thin inner pipe 4 made of corrugated pipe or the like is wrapped around the tip. Inside casing 1, reinforcing bar I1
Built on the outer meaning of 2.

Next, pour fresh concrete 5 into the hole adjustment chamber.

When the ready-mixed concrete 5 is poured to the bottom of the casing 1, the casing 1 is pulled up approximately 1111@f, and when the casing 1 passes the position of the backing 5, the backing 5 expands], and the ready-mixed concrete reaches the outside 11 of the inner pipe 4.・Next, pour fresh concrete into the inner pipe 4 at the top! ◎ At that time, a backing 6 is also provided at the top to prevent fresh concrete from falling into the junction between the inner pipe 4 and the casing 1.

The concrete is subjected to a hardening vk loading test, and at that time, the casing 1 is left as it is and friction cut is performed. After the test, casing 1 is pulled out and reused.

With this construction, the casing and circular pipe are used on the top of the foundation pile to ensure the construction of the 7-socket support section.Furthermore, the casing that receives the foundation pile can be pulled out, and the inner pipe Since it is thin-walled, it can be carried out easily.

[Brief explanation of drawings]

Figures 1, 2, Aml, 4th WJ> Yohi 11Bg
l shows the construction process, and Figures 4 and 7 are cross-sectional views.
J...Backing, 4.Inner pipe, 5.φ concrete,
6. Fist backing. Figure 2 Figure 1 Figure 3 Figure 4

Claims (1)

[Scope of Claims] (Li) A hole is drilled in the ground, the casing is inserted into the ground, reinforcing bars and a thin-walled inner pipe are built into the casing, concrete is poured into the inner pipe, and the upper part of the pile is placed. (2) A method for constructing a foundation pile, characterized in that the casing is removed after a loading test.