A single pile vertical cyclic loading test device and method for simulating high-speed rail load

Abstract

The invention relates to a single-pile vertical circulation loading test device and method for simulating high-speed railway loads. The device comprises a test chamber, a test pile, a counter-force frame, an upper rigid beam, a fixing rod and an upper loading unit, wherein the test chamber is a square steel frame, and the main component of the upper loading unit is an electric vibration exciter, and the electric vibration exciter is suspended above the test box by using the upper rigid beam. The power amplitude, the loading frequency, the loading waveform and the like of the exciter are controlled by a signal controller; a displacement sensor is arranged at the top of the test pile, and a resistance strain gauge is arranged in the pile body direction. The device can simulate the working condition of the vibration load on a foundation of a pile foundation, the vibration amplitude and the vibration frequency of the dynamic load can be adjusted, and the stress and displacement applied tothe pile top and the pile body stress distribution can be measured and automatically recorded; the device is simple in structure and can realize system research on single-pile bearing capacity and deformation characteristics under the action of a long-term vertical circulation load, and has important significance in calculation of the pile foundation bearing capacity and deformation in the pile foundation engineering design.

Description

Technical field [0001] The invention belongs to the technical field of geotechnical engineering and geological engineering geotechnical testing, and specifically relates to a single pile vertical cyclic loading test device and method that simulates high-speed rail load. Background technique [0002] As a commonly used foundation form, pile foundation is widely used in engineering construction, especially suitable for engineering projects that have strict requirements on settlement control and bearing capacity. With the construction and development of wind power, ocean engineering, new energy sources and high-speed railways, pile foundations are increasingly subjected to cyclic loads. Under the action of cyclic load, the bearing and deformation characteristics of pile foundation are different from static load. The bearing and deformation characteristics of a single pile under cyclic loading are a very complicated pile-soil interaction problem, with a complex mechanism and many in...

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Problems solved by technology

Most of the tests only measure the pile top load and displacement, but there is no systematic experimental research on the cyclic variation of key physical quantities such as pile axial force, end resistance, pile-soil interface pore pressure, and earth pressure, so it is impossible to study the effect of cyclic loads. It is more difficult to give a reasonable explanation for the mechanism of pile-soil interaction

In the coastal area, due to the existence of deep soft soil, the bearing capacity of the pile foundation is mainly provided by the pile side friction resistance. The pile side friction resistance will change under the action of cyclic load, thereby affecting the bearing capacity and deformation of the pile foundation, which will have a negative impact on the pile foundation. The engineering nature of the pile foundation is adversely affected

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