The Method Of Determining The Optimal Number And Research About Evaluation Of Effective Energy Of Dynamic Compaction

With the development of the construction,dynamic compaction as a fast and efficient processing technology foundation, its effect is remarkable, simple equipment, easy construction, pollution-free after construction, short construction period, economical, etc. which is widely used. But the theoretical study about reinforced soil compaction impact load is not mature, dynamic compaction foundation design parameters, construction methods and the main control is not perfect indicators, based on the above-mentioned problems, according to a similar principle, the establishment of a large proportion of dynamic compaction impact model tests, made a model test device and test system, rammer impact process and mechanism were studied. Using high-speed camera to take a measured compaction impact the whole process, by the acceleration sensor installed on the rammer, testing rammer acceleration, rammed the point directly below the embedded dynamic earth pressure cells, cutting ring, testing soil internal dynamic stress, soil settlement and other parameters through rammer acceleration, rammer impact stroke,the propagation and attenuation of dynamic stress, tamping settlement, soil settlement analysis, to explore the impact mechanism of dynamic compaction based on that ramming ratio can determine the optimal number and access the effective energy of compaction. The main results are:1. The Dynamic compaction process and compaction test process is similar, which can use the compaction device for dynamic calibration of soil pressure gauge and accelerometer, to provide accurate parameters for dynamic compaction test.2. The time curve of dynamic stress is parabolic attenuation, shape of isosceles triangle, using exponential function fitting analysis of soil dynamic force increases with the depth and the attenuation variation driven stress and hit number relation curve of optimal blow count determination.3. The curve of rammer acceleration exhibits a single peak curve, based on the process curve, with the numerical integration, velocity and displacement-time curve can be obtained, which can lay a foundation to the research of the dynamic compaction rammer impact stroke and tamping rammer effectiveness and the properties of dynamic load impact.4. Through analyze the curve of ramming ratio, which can be performed to determine optimal number of compaction and evaluate the dynamic compaction efficiency,not only to reflect the nature of the rock and soil, but also conducive to select dynamic compaction device of high performance.