薄壁筒桩复合地基在铁路深厚软基加固中的试验研究  

Experimental Study on Composite Foundation Reinforced by Thin-walled Tubular Pile for Deep Soft Ground Improvement in Railway

作　　者：时洪斌 毛忠良 Shi Hongbin Mao Zhongliang(China Railway Fifth Survey and Design Institute Group Co. Ltd. , Beijing 102600, China)

机构地区：[1]中铁第五勘察设计院集团有限公司,北京102600

出　　处：《铁道建筑技术》2016年第11期61-65,85,共6页Railway Construction Technology

基　　金：基金项目:连盐铁路深厚海相软土路基地基加固技术现场试验研究(DL-141009-19)

摘　　要：针对大直径现浇混凝土薄壁筒(管)桩复合地基在连云港地区软土加固的适用性问题,首次在铁路正线进行了加固深厚软土的应用试验。筒桩试验段的试桩情况,反映出了现场面临试桩桩长不达标及混凝土灌注充盈系数过大两个严重问题。采用低应变、静载试验、桩芯土开挖和钻孔取芯等方法,对成桩质量进行了检测。同时检测过程中复核试桩地层条件和试桩成桩特点,发现桩机施工能力不足和工法不合理是产生问题的关键。通过桩机施工能力评价、设备改进和工法优化,满足了工程桩桩长和充盈系数的要求,并通过路基填筑过程中的孔压、沉降和位移监测验证了筒桩复合地基加固铁路软基的良好效果。结果表明:在科学严格的施工过程控制条件下,薄壁筒桩复合地基在铁路软基处理工程中具有很好的应用前景,丰富了深厚软土复合地基处理技术与工程实践。In order to identify the suitability of composite foundation reinforced by cast-in-situ concrete large-diameter thinwalled tubular pile（ CTP or PCC pile） for soft ground improvement in Lianyungang,CTP pile is first introduced for deep soft ground improvement field study in railway regular line. The inadequate length of test piles and the excessive filling coefficient of concrete are revealed by field experimental study. Low strain dynamic testing,static load test,pile inner excavation and drilling core methods are used to detect the quality of piles. Through confirming local geological parameters and features of test piles by drilling,the lower piling capability and unreasonable piling method are found to be the key points of the question. By evaluating piling capability,modifying equipment and optimizing piling method,the standard value of piling length and filling coefficient are realized. And in according to pore pressure,settlement and displacement detecting data during constructing subgrade,the CTP composite foundation is proved to be excellent in practice for deep soft ground improvement in railway. As it turns out,according to strict scientific management of piling process,the CTP composite foundation illustrates a good prospect of application and extension for deep soft ground improvement in railway. Furthermore,treatment processes and engineering practice for deep soft ground composite foundation reinforcement have been expanded by it.

关 键 词：薄壁筒桩 复合地基 软基加固 试验研究 

分 类 号：TU447[建筑科学—岩土工程] U21[建筑科学—土工工程]