先注浆再冻结对粉细砂力学性质影响的低温三轴试验（英文）

发布时间：2019-03-13 14:15

【摘要】：人工地层冻结法中主要存在局部强度不足以及冻胀融沉2个弊端,而预注浆法可以提高粉细砂地层的整体强度及控制冻结后的地层冻胀量,被认为是对人工地层冻结法的有效补充。鉴于预注浆可以有效改善土体的强度及抗渗性,进行了一系列低温三轴剪切试验,研究了单纯冻结与先注浆再冻结2种试验方案对粉细砂抗剪强度的影响。在分析先注浆再冻结提高粉细砂强度效果的基础上,重点分析冷却温度、水灰比、含水量、养护时间以及侧压等对抗剪强度指标及应力-应变曲线峰值处割线模量的影响。研究结果表明:粉细砂抗剪强度随冷却温度的降低而增大,与水灰比、含水量、养护时间呈正比关系;割线模量也随冷却温度的降低而升高,与水灰比、含水量呈正比关系;此外,先注浆再冻结粉细砂土样的黏聚力与温度呈良好的线性关系,与水灰比、含水量呈良好的指数函数关系;内摩擦角与温度、含水量呈良好的幂函数关系,与水灰比呈良好的指数函数关系。该研究结果可为先注浆再冻结粉细砂的力学强度指标分析提供参考,也可为先注浆再冻结工法的水灰比、养护时间选择提供指导。
[Abstract]:There are two disadvantages in artificial formation freezing method: local strength deficiency and frost heaving and thawing settlement. The pre-grouting method can improve the overall strength of fine sand formation and control the frost heaving capacity after freezing. It is considered to be an effective supplement to artificial formation freezing method. Since pre-grouting can effectively improve the strength and impermeability of soil, a series of triaxial shear tests at low temperature were carried out, and the effects of simple freezing and pre-grouting followed by freezing on the shear strength of fine silt were studied. On the basis of analyzing the effect of improving the strength of fine sand by grouting and freezing, the effects of cooling temperature, water-cement ratio, water content, curing time and lateral pressure on shear strength index and Secant modulus at peak value of stress-strain curve are analyzed. The results show that the shear strength of fine sand increases with the decrease of cooling temperature, which is proportional to the ratio of water to cement, water content and curing time, and the Secant modulus also increases with the decrease of cooling temperature, which is proportional to the ratio of water to cement and water content. In addition, there is a good linear relationship between cohesive force and temperature, and a good exponential function relation with water-cement ratio and water content. The internal friction angle has a good power function relation with temperature and water content, and a good exponential function relation with water-cement ratio. The results can be used as a reference for the analysis of mechanical strength index of pre-grouting and then freezing fine sand, as well as for the selection of water-cement ratio and curing time of grouting-freezing method.
【作者单位】：同济大学土木工程学院;北京交通大学土木工程学院;
【基金】：supported by the Natural Science Foundation of Zhejiang Province of China (No.LZ13E080002)
【分类号】：U416.1

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