强夯加固填土的效果与机理分析

Analyses on the results and mechanism of dynamic compactness to fill foundation

针对山区全风化泥岩和粘性土混合回填地基的强夯加固试验工程,采用PLT,DPH和SPT3种方法,测试了夯击能量与夯后时间对强度和加固深度的影响及加固效果的空间变化,评价了测试方法,分析了加强点夯后不同尺寸基底下的承载力与沉降计算方法,更新了有效加固深度的概念与影响因素。研究结果表明:强夯加固素填土,强度随时间增长;竖向形成上硬下软的2层结构;设计承载力时宜指明具体时间和层位;检测时,应根据土质特征选择可行的方法综合评价;夯体与夯间土形成复合地基;有效加固深度取决于土质、强夯参数、基础埋深和基底宽度等。

Based on the test results of dynamic compacting fill foundation mixed with clayey soil and totally weathered mudstone in mountainous area by PLT,DPH and SPT, this paper studies the influence of tamping energy and post-compacting time to both of the strength and depth of treatment, and the space difference of the effect of treatment,evaluates the methods analyses the calculation of bearing capacity and settlement of foundation with many kinds of size after strengthening compacting,and renewed the concept of the effective reinforcing depth and its influence factor.The results show that the plain fill reinforced by dynamic compacting forms a kind of two-layer structure with harder top whose strength increasing with time.The practical time and place should be pointed out while designing the bearing capacity and the effect of treatment should be evaluated synthetically on the basis of both of the soil character and suitable test when the reinforced foundation is checked.The reinforced soil belongs to the composite foundation which is composed of the tamping points and the untamping points. The effective reinforcing depth is related to soil properties,tamping parameters,embeded depth and breadth of foundation,and so on,which is a kind of reinforcing depth being fit for the standard of strength and settlement.