路堤荷载下长板-短桩工法复合地基

提出了长板-短桩工法复合地基的软土地基加固方法：将水泥土搅拌桩法与塑排板排水固结法结合起来，用短的搅拌桩加固上部软土地基，用长的塑料排水板插入深层软土地基，填土预压联合处置深厚软土地基，形成新的联合处理工法．在江苏省淮盐高速公路软土地基处理试验段的监测与测试结果表明：长板-短桩工法复合地基对短桩以下软土的加固效果较好，且有利于提高地基的承载力和稳定性．在长板-短桩工法处理段落，短桩有一定的向下刺入，桩土应力比较小，桩土变形相对协调．通过改变短桩的桩长和桩间距，可以调整地基的总沉降．

Cement Mixing Pile Composite Foundation Combined with Prefabricated Vertical Drain Preloading Under Embankment

The paper presents a new way to consolidate soft soil,that is,the cement deep mixing pile method(DMM) and the consolidation method with prefabricated vertical drains(PVD) are used in combination to consolidate the thick soft soil foundation,with short DMM used to improve the shallow soft soil and long PVD penetrating into the deeper soft soil layers.This approach was applied in an experimental section in Yancheng part of Jiangsu provincial Huaian-Yancheng Expressway,the field monitoring was carried out during the embankment construction and in the preloading period,and the in-situ tests were done at the end of preloading to check the soil properties after improvement.Results show that this new method succeeds in consolidating deep soft soils beneath the DMM pile end and improving the bearing capacity and the stability of the foundation soil.The downward thrust of short pile in the combined improvement section made the stress ratio of soil and pile relatively lower,the settlement on pile and soil more coordinative.The total settlement of foundation could be adjusted through the change of pile length and pile distance.