后注浆对桩周土层加固作用研究*
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（1 杭州天境建筑设计有限公司， 杭州 310009; 2 中国建筑技术集团有限公司, 北京 100013; 3 杭州市居住区发展中心有限公司， 杭州 310000）
［摘要］通过现场标贯试验分析后注浆对桩周土层的加固作用，分别研究不同水灰比浆液注入时，距离桩身不同距离处土体标贯击数的提高情况，并对试验结果进行对比分析。结果表明：后注浆能有效挤密桩周土体，提高土体的标贯击数，距离桩基越近，加固作用越明显；水灰比较小的浆液由于注入性较差，引起的桩周挤密作用更明显，相对于粉土和黏土而言，浆液对砂土的挤密加固作用更好。［关键词］后注浆桩; 标贯试验; 桩周土中图分类号：TU473 文献标识码：A 文章编号：1002-848X(2016)08-0076-03
Reinforcement effect research of post grouting on soil layers around pileBao Liuqing1, Zhou Tao1, Chen Zhebing2, Ye Jianliang3(1 Hangzhou Tianjing Architecture Design Co., Ltd., Hangzhou 310009, China; 2 China Building Technique Group Co., Ltd., Beijing 100013, China; 3 Hangzhou Residential Development Center Co., Ltd., Hangzhou 310000, China)Abstract: The reinforcement effect of post grouting on soil layers around pile was analyzed through field standard penetration test. The improvement situation of soil standard penetration test (SPT) blow counts at soil layers with different distances from the pile was studied respectively when slurries with different water-cement ratios were injected, and the test results were compared and analyzed. The results show that post grouting can effectively compact soil around the pile and improve soil SPT blow counts. The reinforcement effect is more obvious when post grouting is closer to the pile. The injection effect of the slurry with small water-cement ratio is poor so as to bring more obvious compaction effect on soil around the pile. With respect to the silt and clay soils, the compaction and reinforcement effects of slurry on sand are better.Keywords:post grouting pile; standard penetration test; soil around the pile
*杭州市建委科技研究项目（201251）。作者简介：包柳青，高级工程师，一级注册结构工程师，Email：tianren9@vip.sina.com。
