中文摘要：

针对砼芯水泥土搅拌桩复合地基处理高速公路深厚软土段的工程实例,通过地表沉降、分层沉降、深层水平位移、砼芯荷载以及桩土应力比测试,讨论了砼芯水泥土搅拌桩处理深厚软土地基的加固效果,荷载分布和传递规律。测试结果表明：砼芯水泥土搅拌桩对于路基沉降和水平位移控制效果优于水泥土搅拌桩,且横断面差异沉降较小。复合地基的主要压缩量发生在桩顶至砼芯底端一定范围的土体内,沉降发生深度由砼芯控制。砼芯水泥土搅拌桩上部出现负摩阻力,中性点位于砼芯1/3长度处。桩土应力比为水泥土搅拌的2～3倍,与刚性桩相近,桩体承担大部分路堤荷载。砼芯水泥土搅拌桩复合地基排水通畅,超静孔隙水压力消散迅速。路堤荷载下砼芯水泥土搅拌桩工作特性与载荷板试验下的测试结果有所不同。最后从沉降和承载力控制角度给出了砼芯水泥土搅拌桩复合地基的设计方法

英文摘要：

The reinforcement effect, load distribution and transfer mechanism are studied by means of the field tests on an engineering example of deep soft soil ground of highway reinforced by concrete-cored DCM piles. The results indicate that the control effect of settlement and horizontal displacement by using the concrete-cored DCM piles is better than that by using the DCM columns, and the differential settlement of subgrade cross section is small. The settlement occurs mainly in the range from the pile top to the bottom ofprecast core piles. The negative friction lies at the upper of concrete-cored DCM piles and the neutral point is located in the one third length of concrete core. The value of pile-soil stress ratio is 2~3 times that of the DCM columns and close to that of rigid piles. The embankment load is mainly shared by piles. The pore pressure of the composite ground with concrete-cored DCM piles rapidly decreases. The work characteristics of concrete-cored DCM piles of the composite ground with under embankment load are different from those obtained from the plate load tests. Finally, considering the control of settlement and bearing capacity the design method for the composite ground with concrete-cored DCM piles is introduced.