不同改良方案下膨胀土路基物理力学特性  

Physical and Mechanical Properties of Expansive Soil Subgrade under Different Improvement Schemes

作　　者：唐博 何艾雨 TANG Bo;HE Aiyu(Southwest Municipal Engineering Design&Research Institute of China,Chengdu 610081,China)

机构地区：[1]中国市政工程西南设计研究总院有限公司,成都610081

出　　处：《路基工程》2022年第2期195-199,共5页Subgrade Engineering

摘　　要：某中型桥梁修建于膨胀土填土基础上,针对锥坡和台背填土路面开裂病害,剖析病害原因,提出处治方案:分别以水泥、钢渣粉和氢氧化钠激发剂作为复合改良材料,进行多种干湿循环条件下膨胀土改良试验以验证其变形及力学特性;通过无侧限抗压强度试验、三轴压缩试验以及体积变化率试验,结合微观电子扫描显微镜分析方法,对试验结果进行对比。得出结论:经改良后的膨胀土无侧限抗压强度大小结果为PGCJ>PC>PGC>P;在模拟干湿循环环境中改良膨胀土的强度保持较好,且随循环次数的提升而增长;改良膨胀土的体积变化率显著降低;改良剂的加入能增强膨胀土的密实度,从而提升其水稳定性。A medium-sized bridge was built on the foundation of expansive soil fill, aimming at the cracking disease of the conical slope and the backfill pavement of the abutment, the causes of the disease were analyzed and a targeted treatment plan was proposed. With cement and steel slag powder and sodium hydroxide stimulant as a composite improvement material respectively, the expansive soil improvement test is carried out to verify its deformation and mechanical properties under the dry and wet cycle condition. Through unconfined compressive strength test, triaxial compression test and volume change rate test, combined with the microscopic electron scanning microscope analysis method, compares the test results. The following conclusions are drawn: the unconfined compressive strength of the expansive soil after improvement is PGCJ>PC>PGC>P;the strength of the improved expansive soil in the simulated dry-wet cycle environment is maintained well, and it increases with the increase in the number of cycles;the volume change rate of expansive soil is significantly reduced;the addition of modifiers can enhance the compactness of expansive soil, hereby improving its water stability.

关 键 词：膨胀土路基 水泥 钢渣粉 胀缩变形 激发剂 

分 类 号：U443.82[建筑科学—桥梁与隧道工程]