季冻区石灰改良黏性土路基的耐久性  

Durability of Lime-Stabilized Clay Subgrade in Seasonal Frozen Region

作　　者：王永辉 杨超越 王延宁 WANG Yong-hui;YANG Chao-yue;WANG Yan-ning(Second Engineering Co.,Ltd.,China Railway 14th Bureau Group Co.,Ltd.,Taian 271000,China;College of Engineering,Shantou University,Shantou 515063,China)

机构地区：[1]中铁十四局集团第二工程有限公司,泰安271000 [2]汕头大学工学院,汕头515063

出　　处：《科学技术与工程》2024年第34期14787-14795,共9页Science Technology and Engineering

基　　金：国家自然科学基金(41672259);广东省自然科学基金(2022A1515011200);深部岩土力学与地下工程国家重点实验室开放基金(SKLGDUEK2005)。

摘　　要：石灰稳定黏性土是一种应用广泛的路基土改良材料,然而其在季冻区应用时的耐久性评价一直被长期忽视,这对于路基工程的长期稳定具有重要意义。通过对沧州市石港铁路客运专线路基土进行回弹模量和无侧限抗压强度试验,对石灰稳定黏性土的水分及耐久性评价进行了研究总结。水分是影响土壤工程性能的重要因素之一,分别考虑测试样品在最佳含水量、干燥状态和湿状态三种含水量下开展试验研究。结果表明,水分对石灰处理土壤回弹模量和无侧限抗压强度值的影响小于未处理土壤,石灰处理后的回弹模量和无侧限抗压强度值随石灰剂量的增加而增加。耐久性研究是样品在最佳含水量下制备,并在受控环境室中进行10、20次冻融(F-T)循环后进行测试。将F-T损伤样品回弹模量和无侧限抗压强度结果与无F-T损伤样品进行比较。经过20次F-T循环后,未处理土的弹性模量显著降低(>80%)。由于F-T作用,石灰改良土的回弹模量值降低不到35%,因此表现出比未经处理土壤更小的破坏。此外,还在实验室中模拟了现场饱和状态,以观察路面在使用寿命期间的最恶劣润湿状况。未经处理的浸湿样品会完全坍塌,石灰改良土则保持完整性,经过浸泡其模量值没有明显变化。Lime stabilized viscous soil is commonly used for improving subgrade soil.Its moisture and durability evaluation are of great significance to the design and construction of subgrade engineering.Based on the resilience modulus and unconfined compressive strength tests of the subgrade soil of the Shigang Railway passenger special line in Cangzhou,the moisture and durability evaluation of lime-stabilized clay was summarized.Moisture is one of the important factors affecting soil engineering properties,and test samples are prepared under three different molding moisture contents:optimal moisture content,dry state,and wet state.The results show that the influence of water on the resilience modulus and unconfined compressive strength of lime-treated soil is less than that of untreated soil,and the resilience modulus and unconfined compressive strength of lime-treated soil increase with increasing lime dose.The durability study involves samples prepared at optimal water content and tested after 10 and 20 freeze-thaw(F-T)cycles in a controlled environment chamber.The resilience modulus and unconfined compressive strength of the F-T damaged samples are compared with those of undamaged samples.The results indicate that the elastic modulus of untreated soil decreases significantly after 20 F-T cycles(≥80%).Due to the F-T action,the rebound modulus value of the lime-modified soil is reduced by less than 35%and therefore exhibits less damage than untreated soil.In addition,the field saturation state is simulated in the laboratory to observe the worst wetting conditions of the pavement during its service life.Untreated wet samples collapse completely;however,the lime-improved soil remains intact,and its modulus value does not change significantly after soaking.

关 键 词：石灰改良黏性土 回弹模量 无侧限抗压强度 耐久性评价 路基工程 

分 类 号：TU445[建筑科学—岩土工程]