高液限黏土质砾承载比强度特性试验研究

Experimental Studyon Strength Characteristics of the CBR of High Liquid Limit Clay Gravel

高液限黏土质砾属于非均匀、非均质、非连续的混合多相特殊地质材料,其承载比(CBR)强度特性较一般细粒黏土或粗粒填料有较大差异。因此,以我国西南地区某高速公路典型的高液限黏土质砾为研究对象,开展了不同含水率、不同细粒土含量和不同击实功下的CBR试验研究。其结果表明:高液限黏土质砾的CBR强度受颗粒组成、含水率和击实功等因素的综合影响,仅改变单一因素并不一定能提高CBR值;高液限黏土质砾的CBR强度变化比纯黏性土剧烈,受含水率影响更为明显;若不计算砾石的吸水量,高液限黏土质砾中黏土的含水率超过其液限时,黏土起着润滑作用,将明显降低高液限黏土质砾的CBR值;当高液限黏土质砾在最佳含水率时,其CBR值大于8%,可用于路基各层位的填筑;高液限黏土质砾路基碾压施工过程中,需突破以最佳含水率作为碾压含水率控制标准的传统模式,可在对其细粒土含量、压实度、含水率等因素综合考量的基础上,确定最优的碾压参数控制标准。该研究成果可为高液限黏土质砾的合理有效利用提供理论和技术支撑。

High liquid limit clay gravel belongs to heterogeneous,heterogeneous,and discontinuous mixed multiphase special geological materials,and Califonia Bearing Ratio(CBR)strength characteristics are significantly dfferent from those of general fine-grained clay or coarse-grained fillers.A typical high liquid limit clay gravel on a highway in the southwest region is taken as the research object.CBR experimental research were conducted with different moisture content,fine-grained soil content and different compaction work.The results show that the CBR strength of high liquid limit clay gravel is comprehensively affected by factors such as particle composition,moisture content and compaction work.Changing one single factor may not improve the CBR value;The CBR strength of clay gravel varies more dramatically than that of pure cohesive soil,which is more significantly affected by water content;If the water absorption of gravel is not calculated,when the water content of clay exceeds its liquid limit,the clay plays a lubricating role,which will significantly reduce the CBR value of clay gravel;When the clay gravel has an optimal moisture content and its CBR value is greater than 8%,it can be applied for filling various layers of the roadbed;During the compaction construction process of high liquid limit clay gravel subgrade,it is necessary to break through the traditional mode which the optimal moisture content is the control standard for compaction moisture content.Based on comprehensive consideration of factors such as fine-grained soil content,compaction degree,and moisture content,the optimal compaction parameter control standard can be determined.The research results can provide theoretical and technical support for the rational and effective utilization of high liquid limit clay gravel.