中国道路工程中土壤固化技术综述

Review on soil solidified technologies in road engineering in China

为在道路工程建设中更灵活使用不同土壤固化技术并完善固化土规程,对比分析了土壤固化剂对不同土壤的固化效果与适用范围;梳理了道路工程设计和施工规范,统计其对基层与底基层的强度要求,并与固化土规范进行对比,分析了不同等级固化土的强度范围与公路规范要求强度区间的匹配性;结合实际固化强度效果与规范要求,建立了有机固化土与无机固化土在强度要求上的内在联系。研究结果表明:无机、离子、有机3类土壤固化剂对黏土等非特殊土均具有较好的固化效果,有机土壤固化剂具有更广泛的适用范围,且对红土等特殊土表现出更好的固化效果;公路规范中基层不同7 d无侧限抗压强度要求的重叠区间和最小7 d无侧限抗压强度要求各点位组成的下限区间相结合,二者区间交集为[1.5,5.0]MPa,三级固化土最小强度要求为2.5 MPa,与公路交集区间的5.0 MPa差异较大;结合固化土本身特性和不同道路类型与结构层等对材料力学性能的要求,建议将固化土分级体系细化,新增四级[3.0,4.0)MPa、五级[4.0,5.0)MPa和六级[5.0,+∞)MPa3种等级;在现行规范中未有针对有机固化土的技术要求,而其力学性能基本上接近无机固化土,适用范围优于无机固化土,建议后续规范修订中新增有机固化土类别,以便规范化应用。

To enhance the versatility of various soil solidified technologies in road construction and to improve the regulations of solidified soil,a comparative analysis was conducted on the solidified effects and applicability ranges of stabilizers for different soils.Additionally,the specifications of road engineering design and construction were reviewed,and their strength requirements for base and sub-base were analyzed and compared with the solidified soil specifications.The compatibility of strength ranges of different grades of solidified soils and the requirements of the road specifications was studied.The internal relation between organic solidified soil and inorganic solidified soil in the strength requirements was established by integrating the solidified strength effect with the specification requirements in real situation.Research results show that inorganic,ion,and organic soil stabilizers display good solidification effects on non-special soils like clay,etc,whereas organic soil stabilizers exhibit a wider range of application and superior performance in stabilizing special soils like laterite,etc.The overlapping interval of the different 7 d unconfined compressive strength requirements for the base specified in the highway regulations and the lower limit interval comprised of various points for the minimum 7 d unconfined compressive strength requirements were combined to form an intersection interval of [1.5,5.0] MPa.However,the minimum strength requirement for tertiary solidified soil is 2.5 MPa,which greatly differs from 5.0 MPa in the intersection interval in the highway specifications.Considering the characteristics of solidified soil and the diverse requirements of road types and structural specifications on material mechanical properties,it is suggested to refine the grading system of solidified soils by introducing three new grades:Grade Ⅳ [3.0,4.0) MPa,Grade Ⅴ [4.0,5.0) MPa,and Grade Ⅵ [5.0,+∞) MPa.There is no technical requirement for organic solidified soil in the current specifications and its mechanical properties are basically close to inorganic solidified soil.Its scope of application is better than inorganic solidified soil,so it is suggested that the subsequent revision of the specifications adds organic solidified soil category for standardized application.13 tabs,16 figs,85 refs.