花岗岩残积土填料路用工程特性室内试验研究

为了研究花岗岩残积土的路用工程特性，通过击实试验、承载比CBR试验、固结试验以及室内基床系数试验分析了该类材料压实性能及基本力学特性，对压实度为92%的最优含水率和饱和压实土样进行了循环加载试验，研究了动力荷载作用下土体的变形特性。结果表明，花岗岩残积土在K为91%～97%时压实功效率较高，提高压实度对于增强土体局部抗变形能力较为有效；采用室内三轴法得到的基床系数K30值为188.25 MPa/m；最优含水率下花岗岩残积土动力变形稳定性较好，但含水率增加会大幅度增加土体塑性变形，降低土的动弹性模量，不利于变形稳定。所以作为路堤填料，应考虑作为受气候与动荷载影响较小的下路堤备用填料，作为铁路路堤本体及公路上、下路路床填料，应在进行土性改良且满足要求的论证基础上取舍。研究成果可为花岗岩残积土填料的工程应用及土体改良提供技术参考。

Indoor experimental study of road performance of granite residual soil for subgrade filling materials

In order to research the road performance of granite residual soil subgrade filling materials, compaction characteristics and mechanical properties of compacted residual soil are researched by using compaction test, California bearing ratio(CBR) test consolidation test and indoor test method for coefficient of subgrade reaction. The deformation properties of the soil under dynamic loads are studied by using cyclic loading test on the optimum moisture content and saturated samples. The results show that compaction works more efficiently with K of 91%-97% for granite residual soil. Improving the degree of compaction is effective to enhance the local deformation resistance of the soil. K30 was obtained from indoor triaxial test, and the value is 188.25 MPa/m. The dynamic stability of granite residual soil is comparatively well under the optimum moisture content. However the plastic deformation increases substantially and dynamic elastic modulus reduced with water content increasing. The increasing water content is not conducive to the deformation stability of the soil. So as filling materials, it shall be considered as spare materials of embankment which suffers low effect of environment. If used as subgrade body and highway roadbed, shall be modified and making choice based on the requirements of deformation. This study may provide technical reference for the construction process of granite residual soil as embankment filling and soil conditioning.