The Research Of Techniques For Accumulative Charge To Excavate Foundation Protected Level

The excavating method of protected level of foundation for hydraulic structure is concemeted with the quality,progress and benefits of engineering. The improper excavating will bear capacity, water permeability, natural structure and geological structure worsenning the base rock of foundation . , This can't be allowed to the water conservancy project building, especially to block water building.lt will not only increase the expenses happened of the remedy measure ,but also lengthen building straight line time limit for a project of construction. It is of paramount importance for adoptint advanced , fast and reliable method of excavating building foundation.For reducing cost and accelerating construction speed sparingly, at present in irrigation works construct in producing testing progressively and antiabrasion layer that popularize excavating method competent to split law in advance, flexible cushion layer etc. Accumulative charge to vertical hole has been tested in three gorege project only. This method has carried on rougher qualitative analysis only on the principle, has not formed the comparatively systematic theory . This paper is on the basis of analysedding and summarized that these projects were blown up and tested materials in the past, use fracture mechanics, the dynamics blast theory and finite element analytical method, have carried on the system, detailed analysis and describes to this kind of method of blasting, proving theoretically that can cut the base rock effectively in this kind of method of blasting, reduce base blowing up stress value inside the rock , play and protect underpart base rock blow up into the function influenced in vibration, and blew up mechanism and analysed the main influence factor blown up according to it, had put forward the rational optimization measure to the relevant parameter when implementedding and blown up . Include the following several respects basically:(1)According to blast dynamics theory, research calculate gather can powder bag cut base rock form in the range of the crack when blowing up individually, analyse that proving can gathers the function of cutting the rock of powder bag.(2)Use finite element analytical method , go on and gather can powder bag invade and cut to blow up simulation number value calculate rock, analyse in conformity with development of Reeb, propagate, decay course , can blow up and down base rock characteristic of the stress go on research gathering, have proved that can gathers the result of cutting the rock of powder bag.(3)Principle analyse produce powder bag stress produced to explode involve and produce and catch gas can cut function mechanism that crack expand further gathering mainly according to fracture mechanics.(4)What has cut the crack and expanded further has blown up simulation number value to calculate, expand the function played on the crack after verifying the main powder bag.(5)ln excavating in the base hole of the second stage of the project of Sanxia, the powder bag is blown up and tested after goning on and can gather, and blows up and tests the optimization and scene which blows up the parameter according to the analysis achievement of finite element, have made certain test achievement. Question that should be paid attention to when discussed this kind of relevant influence factor while blowing up and construct, have proposed that accumulative charge, blowing up the optimization in factors, such as parameter,etc. to choose the method, suitable for other projects to draw lessons from .