重力式码头墙后回填改良土应用研究

刘冰冰¹，宋志坚²，王日升^1*，赵月航¹

1.山东交通学院交通土建工程学院，山东 济南  250357；2.泰安市通达投资有限公司，山东 泰安  271000

摘要：为检测将水泥与干土的质量比为8%的水泥改良土作为重力式码头墙后回填物的承载力，基于无侧限抗压强度试验、抗剪强度试验、点荷载试验及承载比试验等室内试验，采用无损检测方法电阻率法，研究单应力场作用下，含水率分别为7.7%、9.7%、11.7%、13.7%、15.7%、17.7%、19.7%的水泥改良土试件的力学性能变化规律以及电场响应特性。试验结果表明：1）不同含水率下，试件电阻率均随荷载和位移的增大先迅速减小后趋缓；高含水率试件的初始电阻率较含水率低的试件小，含水率越大，试件最终位移越大。无侧限抗压强度与初始电阻率、破坏电阻率的相关性较高，可采用电阻率法评价水泥改良土的力学强度特性。2）在剪切试验中，不同含水率下水泥改良土试件的最大电阻率均随法向应力增大而减小，试件电阻率随剪切位移的增大而增大，抗剪强度随破坏电阻率的增大而减小，破坏电阻率随含水率的增大而减小，最大抗剪强度随含水率的增大而先增大后减小。3）在干湿循环下点荷载试验中，试件的单轴抗压强度随含水率的增大而先增大后减小，二者呈高斯函数关系；试件的电阻率随含水率的增大而减小，二者呈指数函数关系。在无侧限抗压强度试验中，试件的单轴抗压强度随电阻率的增大先增大后减小，二者呈二次抛物线关系。4）在承载比试验中，承载比随试件含水率的增大而先增大后减小，二者呈高斯函数关系；试件的电阻率随含水率的增大总体减小；承载比随试件电阻率的增大而先增大后减小，二者呈二次抛物线函数关系。

关键词：改良土；应力场；电阻率；承载比

Application of improved soil backfill behind gravity dock walls

LIU Bingbing¹, SONG Zhijian², WANG Risheng^1*, ZHAO Yuehang¹

1.School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China; 2.Taian Tongda Investment Co., Ltd., Taian 271000, China

Abstract: To detect the bearing capacity of cement-modified soil with a cement-to-dry-soil mass ratio of 8% as backfill material for gravity-type dock walls, indoor tests such as unconfined compressive strength tests, shear strength tests, point load tests, and California bearing ratio tests are conducted. Using a non-destructive testing method, the mechanical properties and electric field response characteristics of cement modified soil specimens with water content of 7.7%, 9.7%, 11.7%, 13.7%, 15.7%, 17.7% and 19.7% are studied under the action of single stress field. The test results indicate: 1) Under different moisture contents, the resistivity of the specimens decreases rapidly with the increase of load and displacement, and then tended to stabilize. The initial resistivity of specimens with high moisture content is lower than that of specimens with lower moisture content; as moisture content increases, the final displacement of the specimens also increases. The unconfined compressive strength is highly linearly correlated with the initial resistivity and the failure resistivity, indicating that the resistivity method can be used to evaluate the mechanical strength characteristics of cement-modified soil. 2) In shear tests, the maximum resistivity of cement-modified soil specimens under different moisture contents decreases with increasing normal stress, while the resistivity of the specimens increases with increasing shear displacement. The shear strength decreases with increasing failure resistivity, and failure resistivity decreases with increasing moisture content. The maximum shear strength first increases and then decreases with increasing moisture content. 3) In point load tests under dry-wet cycles, the uniaxial compressive strength of specimens increases and then decreases with increasing moisture content, following a Gaussian function relationship. The resistivity of the specimens decreases with increasing moisture content, following an exponential function relationship. In unconfined compressive strength tests, the uniaxial compressive strength of the specimens increases and then decreases with increasing resistivity, following a quadratic parabolic relationship. 4) In bearing ratio tests, the bearing ratio increases and then decreases with increasing moisture content of the specimens, following a Gaussian function relationship; the resistivity of the specimens generally decreases with increasing moisture content. The bearing ratio increases and then decreases with increasing resistivity of the specimens, following a quadratic parabolic function relationship.

Keywords: improved soil; stress field; resistivity; California bearing ratio