Study On Application And Restriction Of Low Stress Reflected Wave Dynamic Test For Manual Holing Cast-in-place Pile's Integrity

As a kind of no-damage indirect test, low stress reflected wave dynamic test has become a major method of pile test. It is widely used in field of pile test in our country and is popularly applied in test for manual holing cast-in-place pile mostly adopted in our country, which achieves quite good effect.Based on investigation of previous research on restriction of low stress reflected wave dynamic test for pile body's integrity, author of this paper find out these research production mainly concern studies on "dimension effect" taking place when stress wave is being transmitted and hardly refer to restriction of low stress reflected wave dynamic test for pile body's integrity under influence of manual holing cast-in-place pile's technique and geological layer surrounding the pile. Thus this paper carries out the research on this kind of restriction in combination with a power station construction project in Hunan province and main studies and achievement are as follows:1.Basic theory of low stress reflected wave dynamic test is explained and meanwhile transmission feature of stress wave in manual holing cast-in-place pile body is analyzed to discuss characteristics of restriction of low stress reflected wave dynamic test for manual holing cast-in-place pile body's integrity.2.Technological points about collection and analysis of tested curve in this subject is summarized and analysis of pile body's integrity, from the aspect of low stress reflected wave dynamic test, is given to some manual holing cast-in-place piles whose curves are special in form.3.Verification project of low stress reflected wave dynamic test's result comprising selection of verification methods and assistant analysis means adopted in verification process as well as technological points of verification is planed.4.Through carrying out the verification project, various of factors affecting test in a power station construction project are analyzed to discuss restriction of low stress reflected wave dynamic test for manual holing cast-in-place pile body's integrity in combination with method of contrast and validate which is used to eliminate interference so that integrality of pile body is correctly judged, which has a definite reference value for future pile test of same condition.