新型粉喷桩加固海相软土地基的应用效果评价  

Evaluation of Application Effect of Soft Marine Clay Foundation Reinforced by New Dry Jet Mixing Piles

作　　者：谢胜华[1,2] 刘松玉[1] 杜广印[1] 

机构地区：[1]东南大学交通学院,江苏南京210096 [2]安徽工业大学建筑工程学院,安徽马鞍山243002

出　　处：《中国公路学报》2014年第1期8-14,共7页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(41372308);高等学校优秀青年人才基金项目(2012SQRT037);江苏省交通科技项目(08Y33)

摘　　要：为检验新型粉喷桩加固海相软土地基的应用效果，结合江苏连云港至山东临沂高速公路软基处理工程，开展了2种新型粉喷桩（双向粉喷桩和钉形粉喷桩）与常规粉喷桩加固海相软土地基的现场对比试验，介绍了新型粉喷桩的设计和施工参数，进行了粉喷桩复合地基载荷试验和路堤填筑期桩土差异沉降、桩土应力比、孔隙水压力、水平位移与地表沉降等项目为期1年的现场测试。结果表明：新型粉喷桩较常规粉喷桩具有复合地基承载力高、工后沉降小的特点，填筑稳定时桩土应力比在1．5～2．0之间；设置碎石垫层后有利于减小桩体向路堤填土的刺入变形，确保桩土变形协调一致，有效减少桩土差异沉降，且能够减少水平侧向位移，缩短桩周土孔隙水压力消散时间，进而加快路基固结稳定时间，最终达到快速、有效地加固海相软土地基的效果。In this paper we conducted contrastive experiments to verify the effect of soft marine clay foundation reinforced by two new types of dry jet mixing piles and conventional piles based on an expressway project from Lianyungang in Jiangsu Province to Linyi in Shandong Province to check the effect of soft marine clay foundation reinforced by the new dry jet mixing piles. Two new types of dry jet mixing （DJM） piles, including bidirectional DJM ones and nail-shaped ones, were presented with their designs and construction parameters. We carried out one-year on-site testing on the static load of composite foundation and the differential settlement between piles and soil, pile-soil stress ratios, pore water pressure, horizontal displacement and ground settlement during the period of embankment construction. The results show that both soft marine clay foundations reinforced by new types of DJM piles have better bearing capacities and settle less after construction. Moreover, the pile-soil stress ratio should be set between 1. 5 and 2.0. In addition, the establishment of gravel cushion reduces the stab deformation from the pile to the embankment, to guarantee the pile-soil deformation coordination, effective reduction of the differential displacement between piles and soil and the horizontal lateral displacement. These improvements can shorten the water pressure dissipation time from pile-soil pores andsubsequently speed up the stability of roadbed consolidation to achieve a quick and effective consolidation of soft marine clay foundation.

关 键 词：道路工程 复合地基 试验研究 承载特性 海相软土 加固效果 

分 类 号：U416.1[交通运输工程—道路与铁道工程]