Method and device for detecting strain/stress of pile body by prestress pipe file field static load test

Abstract

The invention discloses a method for detecting the strain / stress of a pile body by a prestress pipe pile field static load test, comprising the following steps of: pre-burying a strain gauge in a prestress pipe pile; leading out a lead in the piling process of the prestress pipe pile; before producing the prestress pipe pile, pre-burying an additional reinforcing steel bar with the stress gauge in a reinforcing cage, leading the lead connected with the stress gauge to a near-end part of the steel reinforcing bar of the reinforcing cage along the additional steel reinforcing bar and fixing the lead, placing the reinforcing cage in which the additional reinforcing steel bar with the stress gauge is buried into a steel die produced by the prestress pipe pile and producing the prestress pipe pile according to a normal production process except high-pressure steam curing; and binding all leads of each pipe pile during piling on the fixed device at the position of the section of the pipe pile, which is close to the end part, pulling all leads of next section of pile during pile connection to the fixed device of the last section of pile from a pile cavity and fixing and leading out the leads from the end head at the top of the pile, on which a groove opening is arranged in advance. The invention is applied to the field of civil construction engineering, can be simply and conveniently operated and has high precision and favorable economy.

Description

Technical field [0001] The invention relates to the technical field of pile body strain / stress detection in civil engineering, and specifically refers to a pile body strain / stress detection method and device for on-site static load test of prestressed pipe piles. Background technique [0002] Prestressed pipe piles (usually referred to as concrete pipe piles) are used as the foundation of civil engineering such as house building structures and bridge structures, and are more and more widely used in engineering. However, the force mechanism of the pile is affected by the characteristics of the pile’s technology and soil. , The material properties of the pile, the geometric characteristics of the pile, load and many other factors, even under the action of vertical load or horizontal load, the mechanism of stress transfer to the surrounding soil has not been fully understood. The on-site static load test of prestressed pipe piles is one of the effective methods to determine the bear...

AI Technical Summary

Problems solved by technology

Existing detection technology usually can only obtain the vertical load of the pile and the vertical displacement of the pile top and the correlation relationship during the vertical static load test, and the horizontal load of the pile and the horizontal displacement of the pile top and the correlation relationship during the horizontal load static load test. The strain (stress) relationship distributed along the pile body under load can be obtained more accurately, and the distribution of pile side friction resistance and the pile tip resistance cannot be determined more accurately.

[0008] (2) It is impossible to reasonably explore the mechanical characteristics and stress transfer mechanism of piles: although prestressed pipe piles have been widely used in practical engineering, the load-bearing characteristics of piles under different soil layers, different bearing layers, and different pile lengths are different. The force characteristics and stress transfer mechanism are not yet completely clear, and further research is still needed. The measured data of the relationship between the vertical (horizontal) load and the vertical (horizontal) displacement of the pile top obtained by the existing detection technology cannot meet the requirements of the study. Requirements for pile mechanical characteristics and stress transfer mechanism

This method is more convenient, but the backfilled reinforced concrete will greatly change the stiffness of the pipe pile, so that the pile body compression and pile top settlement properties obtained in the test are difficult to approach the actual engineering

[0013] These two improved detection techniques also have the following disadvantages: due to the small inner diameter of the pipe pile, the distance between the two strain gauges of the same section is relatively short, and the error in calculating the bending moment is relatively large

Similarly, the change of stiffness has a great influence on the horizontal load-bearing performance of piles, which cannot reflect the horizontal load-bearing performance of tubular piles well.

Images