水泥改良风积沙无侧限抗压强度试验研究

Experiment Research on Unconfined Compressive Strength of Cement Improved Aeolian Sand

针对蒙西华中重载铁路风积沙路段缺少路基优质填料的工程实际,采取就近取材的原则,采用水泥改良风积沙填筑路基基床底层.开展室内水泥改良风积沙无侧限抗压强度试验,研究不同水泥掺量、养护龄期、压实系数和水泥强度等级下试件强度变化规律,探讨水泥改良风积沙填筑重载铁路路基基床底层的适用性.试验结果表明:水泥改良风积沙强度随水泥掺量、压实系数的增大而提高,并存在良好的线性和多项式拟合关系;龄期效应对其强度影响显著,相比水泥改良粉土、黏性土等其它细粒土,前期强度增长速率较快,而后期强度增长速率较慢,增长量变小;结合工程实际和室内试验结果提出适合该重载铁路风积沙改良选用水泥等级及水泥掺量的控制标准.

In view of the practice that high quality filling is lack in aeolian sand area in the heavy haul railway which is from the Nei Monggol Autonomous Region to Jiangxi Province,cement im- proved aeolian sand is provided to fill the bottom layer of subgrade bed based on the principle of borrowing soil nearby. Unconfined compressive strength tests for cement improved aeolian sand are performed. The influences of cement content, curing age, compacting factor and cement strength grade on the unconfined compressive strength of cement improved aeolian sand are stud- ied,and the applicability of the cement improved aeolian sand filling the bottom layer of subgrade bed has been discussed. The test results show that the strength of cement improved aeolian sand increases with both cement content and compacting factor, and between them there is well linear relationship and polynomial relationship respectively. Curing age has a significant influence on strength of cement improved aeolian sand. Compared with cement improved silt and cement im- proved clay, the initial strength growth rate of cement improved aeolian sand is faster, and its strength growth rate in later period is slower. Combining with the engineering practice and test results, the appropriate cement strength grade and cement content for cement improved aeolian sand in the heavy haul railway are suggested.