采用小载荷板试验资料推求大型复合地基P～S曲线的方法

Empirical Method For Ascertaining P-S Curve of Large Compound Foundation with Small Load-plate Test Data

经振冲加固处理后的地基为复合地基，该地基由碎石桩和桩间土组成，通过载荷试验可以获得P～S关系曲线（P为荷载，S为沉降量）．经理论论证和多种试验还得出，软粘性土容许承载力与载荷板宽度增大影响不大，而对于砂类土和砾石类土载荷板定度影响明显．基于以上原理分别建立了利用小载荷极试验资料推求各类土的大型复合地基的P～S曲线关系式，求得数值与载荷试验相一致，这样就找到了在中小型工程中可以只作小载荷试验而求出大型复合地基P～S曲线的方法，减少了工作量，节省了投资．

The foundation compacted by vibroflatation becomes a compound one, consisting of stone columns and soil between them. The P-S curve of foundation (P instead of load, S instead of settlement value) can be obtained by loading test. The test results showed that in the soft clay, increasing the width of the loading plate has little influence on the standard bearing capacity obtained, but in the sandy and gravelly soils, the width presents an abvious influence. Basis on the mentioned principle,the relation expression for the P-S cure of large compound foundation of various soils is formulated wlth the data of small loading test. By checking, the calculated values are in accordance with that in loading test. So, for middle or small sized projects, the P-S curve of large compound foundation can be obtained only by using of the small load-plate test. Using this method, the work quantities can be reduced and the construction cost can be saved.