| Method of dynamic compaction is one method with good economy and efficiency to improve foundation. It has good developmental prospect in Guangxi. However, the theory of dynamic compaction is still immature. Some problems aren't clear. Parameter for construction was basically determined on experience, which is unreasonable sometimes.In this paper, some mechanisms without clearness about dynamic compaction were researched by model experimentation. At the same time, the reality that deformation of soil must be taken place in improvement zone was used. The main aspects researched were as follows: The relationship between hammer quality and improvement effect when impact energy and end area of hammer were in same condition; The relationship between end area of hammer and improvement effect when impact energy and hammer quality were in same condition; Comparison of soil deformations caused by dynamic and static load. Some conclusions were gained, which included: It is direct proportion between total improvement effect and hammer quality. More hammer quality, more total improvement effect; Total improvement effect of dynamic compaction is more correlative with hammer quality than hammer dimension; Improvement degree of dynamic compaction is more correlative with hammer dimension than hammer quality. So it should to choice flexibly hammer according to different improvement aim and geological condition to improve work efficiency. Using the result about colliding time in elastic collision theory and the impulse formula explained the relationship between improvement effect and hammer quality, hammer dimension, modulus of elasticity of soil. After analyzing Distribution of stress and deformation of soil caused respectively by dynamic and static load, comparability in two status was found.Finally, the known calculating methods about effective improvement depth were discussed in this paper, and they were not so perfect by so far. New advises were made on effective improvement depth. |
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