Self counter force balance loading test method of engineering pile bearing capacity

Abstract

The invention provides a method for ensuring the position of a load box and pile quality and effectively transmitting axial force, shearing force and bending moment in self counter force balance loading test of engineering pile bearing capacity. A built-in jack of the load box is connected with a top cover plate and a bottom cover plate through high strength bolts, without being affected for normal loading, and consequently the load box transmits certain bending moment. The periphery of the load box is provided with twisted steels that are mutually lapped together and protected by a telescopic pipe, and mudjacking and solid joints are conducted after test, so that a reinforcing cage achieves the effect of overall equivalent connection and bears great shearing force and bending moment. The load box and the reinforcing cage are connected by means of inside cutting, and the horizontal resistance of a pile is increased at the load box. The surrounding gap of the pile is mudjacked at the load box after test to keep the continuity and integrity of pile concrete and ensure the axial force transmission of the pile and the vertical bearing capacity. The bottom of the bottom cover plate of the load box is provided with a conical flow guide body in order to avoid mud and sediments remaining on the bottom of the bottom cover plate when the pile concrete passes through the load box in pouring and ensure the pile quality and test accuracy.

Description

technical field [0001] The invention relates to a method for testing the bearing capacity of engineering pile foundations of fixed buildings such as bridges, and is especially suitable for testing the foundation bearing capacity of bored piles and bored piles. The method of force self-reaction balance loading test. technical background [0002] With the rapid development of large-span structures in our country, a large number of pile foundations are used for structural foundations, and the pile foundations are developing towards long, deep, and general trends, and the bearing capacity of foundations is also increasing; the traditional static load test pile method is faced with large tonnage. Test piles have the disadvantages of high cost, large amount of engineering, and long construction period. For complex test piles on water, slopes, etc., the traditional static load test pile method is more difficult to meet. The force self-balancing test method came into being. In the...

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Problems solved by technology

[0002] With the rapid development of large-span structures in our country, a large number of pile foundations are used for structural foundations, and the pile foundations are developing towards long, deep, and general trends, and the bearing capacity of foundations is also increasing; the traditional static load test pile method is faced with large tonnage. Test piles have the disadvantages of high cost, large amount of engineering, and long construction period. For complex test piles on water, slopes, etc., the traditional static load test pile method is more difficult to meet. The force self-balancing test method came into being

In the prior art, the pile foundation bearing capacity self-balancing test method is only applied to test piles. For example, the utility model patent No. ZL200720088950. After the pile bearing capacity test is completed, the test pile is often discarded, and the load box as the loading device is also buried in the test pile and cannot be reused, causing a lot of waste. If the pile foundation bearing capacity can be directly self-balanced on the engineering pile Test method test, then can save a large amount of test pile pile cost; In the prior art, it is not considered to carry out the self-balancing test method of pile foundation bearing capacity directly on the engineering pile, mainly because the embedding of the load box in the loading device weakens the pile. The transmission of body axial force, shear force and bending moment has affected the normal use of engineering piles, and has the following defects: 1. The burial of the load box divides the pile body into upper and lower parts. When the pile body bears a large horizontal force or When the design has special requirements, the installation position of the load box cannot provide sufficient resistance to the bending moment; 2. After the test is completed, there will be a circumferential gap on the top surface of the bottom cover of the load box, and the integrity and continuity of the pile body will be destroyed, which will affect the stability of the pile body. Vertical bearing capacity; 3. When pouring concrete on the pile body and passing through the load box, it is easy to leave mud and sediment at the bottom of the bottom cover plate of the load box, which will have an impact on the bearing capacity test effect and the quality of the engineering pile

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