多因素影响下石灰固化盐渍土抗剪性能的试验研究

An experimental study of the shear properties of the solidified saline soil with lime concerning under the influence of multiple factors

北方地区季节性的冻融作用影响固化土的强度及变形特性。以冻融次数、含盐量、改性聚乙烯醇掺量(SH固土剂)、石灰掺量、养护龄期及干密度为影响因素,经正交试验设计及三轴UU压缩试验,获取固化盐渍土冻融后的抗剪强度及应力-应变性能。试验表明:试样冻融后的抗剪强度与改性聚乙烯醇掺量、石灰掺量、养护龄期和干密度呈正相关,与含盐量呈负相关;干密度和含盐量为影响固化盐渍土的黏聚力和内摩擦角的主要影响因素,冻融后土的抗剪强度逐渐降低,但抗变形能力逐渐增强,试样呈"鼓"型或弱脆性破坏;抗冻融效果最好的条件为:0.9%改性聚乙烯醇掺量与14%石灰掺量、干密度1.70 g/cm3、养护28 d、含盐量1%和冻融循环3次。

Freezing-thawing action has a great effect on the strength and deformation properties of solidified saline soil in northern China. Factors of freezing-thawing cyclic number, salt content, modified ethylene alcohol content （SH soil fixing agent）, lime content, curing age and dry density are considered, and the orthogonal design and unconsolidated undrained triaxial compression tests are conducted to obtain the shear strength and stress-strain properties of the solidified soil. The results indicate that （ 1 ） shear strength is positively correlated with the modified ethylene alcohol, lime content, curing age and dry density under the freezing-thawing action, and it is negatively correlated with salt content. （2） Dry density and salt content are the key factors affecting the cohesion and the internal friction angle of the solidified saline soil. （3） Shear strength and deformation of the soil experienced freezing and thawing are decreased and the drum-shaped plastic deformation or the weakly brittle failure appear in the soil samples. The suitable scheme is composed of 0.9% of the modified ethylene alcohol with 14% of lime content, 1. 7 g/cm3 of dry density, 28 d of conservation, 1% of salt content, and 3 times of cyclical freezing and thawing.