水泥搅拌桩强度影响因素的试验研究
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摘要
对水泥搅拌桩桩身的强度测试,施工现场与《水泥土配合比设计规程》中所述室内试验在取样方法上存在差异,导致现场检测与室内试验结果间产生差异。本文分别采用原状土和风干土制备水泥土试样,模拟施工现场和室内试验原材料,研究原材料不同、水泥掺入比和水灰比等配合比参数不同对水泥土无侧限抗压强度、抗剪强度的影响规律。当水灰比为2.0,水泥掺入比分别为15%、18%、20%时,水泥掺入比的变化对两类水泥土的无侧限抗压强度和黏聚力的影响均不明显。当水泥掺入比为20%、水灰比分别为1.3,1.5,1.7时,两类水泥土的无侧限抗压强度和黏聚力均随水灰比的增大而减小。配合比设计参数相同时,风干土样水泥土的无侧限抗压强度和黏聚力均高于原状土样水泥土,而原状土样水泥土的内摩擦角则略大于风干土样水泥土。试验结果显示,风干土样水泥土的强度测试结果与原状土样水泥土之间存在显著差异,采用根据规范试验方法所得的力学性能指标指导实际工程将偏于危险。
The sampling methods of cement mixing pile strength testing in construction site and "Specification for mix proportion design of cement soil" are different. The strength testing results of cemented soil which are from references are significantly different from the on-site testing results. In this study, the unconfined compressive strength and shear strength of two types of cement-soil mixing specimens are tested in order to simulate the difference between construction site and laboratory test. One type of specimens is made from undisturbed soil, the other is made from air dried soil. The influences from cement ratio, water-cement ratio on unconfined compressive strength and shear strength of cement soil are studied. When water-cement ratio is 2.0 and cement ratio is 15%, 18% and 20%, cement ratio has no obvious influence on unconfined compressive strength and cohesive strength. When cement ratio is 20% and water-cement ratio is 1.3, 1.5 and 1.7, unconfined compressive of two type cement soil decreases with water-cement ratio increasing. When mix proportion design parameter is the same, both unconfined compressive strength and cohesive strength of cement-air dried soil are bigger than that of cement-undisturbed soil and internal friction angle of cement-undisturbed soil is slightly bigger than that of cement-air dried soil.
The sampling methods of cement mixing pile strength testing in construction site and "Specification for mix proportion design of cement soil" are different. The strength testing results of cemented soil which are from references are significantly different from the on-site testing results. In this study, the unconfined compressive strength and shear strength of two types of cement-soil mixing specimens are tested in order to simulate the difference between construction site and laboratory test. One type of specimens is made from undisturbed soil, the other is made from air dried soil. The influences from cement ratio, water-cement ratio on unconfined compressive strength and shear strength of cement soil are studied. When water-cement ratio is 2.0 and cement ratio is 15%, 18% and 20%, cement ratio has no obvious influence on unconfined compressive strength and cohesive strength. When cement ratio is 20% and water-cement ratio is 1.3, 1.5 and 1.7, unconfined compressive of two type cement soil decreases with water-cement ratio increasing. When mix proportion design parameter is the same, both unconfined compressive strength and cohesive strength of cement-air dried soil are bigger than that of cement-undisturbed soil and internal friction angle of cement-undisturbed soil is slightly bigger than that of cement-air dried soil.
引文
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[14] 涂帆,常方强.水泥土无侧限抗压强度影响因素的室内试验研究[J].工程勘察,2005,(3):8-10.
[15] 郑少辉,赖汉江,章荣军,等.不同水灰比水泥固化黏土的强度特性试验研究[J].地下空间与工程学报,2014,10(6):1281-1284+1292.
[2] 陈甦,宋少华,沈剑林,等.水泥土配合比试验研究[J].中外公路,2006,26(6):166-170.
[3] 朱大宇.水泥土抗压强度影响因素的试验分析[J].建筑技术,2006,37(3):218-220.
[4] 高松鹤.不同水泥土力学性能试验研究[J].施工技术,2014,43(S2):84-89.
[5] 周海龙,申向东,薛慧君.小龄期水泥土无侧限抗压强度试验研究[J].山东大学学报,2014,44(01):75-79.
[6] 周丽萍,申向东.水泥土力学性能的试验研究[J].硅酸盐通报,2009,28(02):359-365.
[7] 钱震生.水泥掺入比、水泥浆水灰比对水泥土强度的影响[J].福建建材,2011,(6):8-9.
[8] 陈文昭,高全臣.水泥土力学性能最优拌合水量的试验研究[J].建筑科学,2010,26(5):10-13.
[9] 水泥土配合比设计规程:JGJ/T 233- 2011[S].北京:中国建筑工业出版社,2011.
[10] 梁志荣,李忠诚,刘江.水泥土搅拌桩取芯与取浆两种强度检测分析[J].岩土工程学报,2010,32(S1):435-439.
[11] 梁志荣,李忠诚,刘江.三轴水泥土搅拌桩强度检测试验分析[J].岩土工程学报,2010,32(S2):475-478.
[12] 唐咸燕.水泥土搅拌桩室内配比试验和现场检测实例分析[J].建筑科学,2013,29(7):109-111.
[13] 杨崇明,王军.水泥搅拌桩室内配合比试验研究[J].现代交通技术,2005,(6):25-28.
[14] 涂帆,常方强.水泥土无侧限抗压强度影响因素的室内试验研究[J].工程勘察,2005,(3):8-10.
[15] 郑少辉,赖汉江,章荣军,等.不同水灰比水泥固化黏土的强度特性试验研究[J].地下空间与工程学报,2014,10(6):1281-1284+1292.