兰州水泥改良黄土拉压强度对比试验研究

Comparative Test Study on Tensile and Compressive Strength of Cement-improved Loess in Lanzhou Region

对宝鸡—兰州客运专线王家沟隧道黄土及其水泥改良土进行室内无侧限抗压、轴向劈裂和单轴拉伸试验,分析含水率和压实度对黄土及水泥改良黄土强度特性的影响,量化分析水泥改良效果。试验结果表明:重塑黄土和水泥改良黄土的抗拉强度远小于其抗压强度;黄土改良前抗压强度为51～229 kPa,抗拉强度为4. 42～18. 37 kPa;改良后抗压强度为1 388～4 196 kPa,抗拉强度为99. 69～250. 75 kPa;黄土经掺加5%水泥改良后,抗压强度提高17倍,抗拉强度提高12倍,改良效果明显;含水率、压实度对重塑黄土与水泥改良黄土强度影响的变化趋势相同,但对重塑黄土强度特性的影响更显著。

Through the unconf ined compression test,axial splitting test and uniaxial tensile test,the effects of water content and compaction on the strength properties of loess and cement-improved were analyzed,and the cement improvement effect was quantitatively analyzed.The engineering background is the Wangjiagou tunnel in Baoji-Lanzhou passenger dedicated line.The test results show that the tensile strength is much lower than the compressive strength for loess and cement improved loess.Without the improvement,the compressive strength is 51~229 kPa and the tensile strength is 4.42~18.37 kPa.With the improvement,the compressive strength is 1 388~4 196 kPa and the tensile strength is 99.69~250.75 kPa.After the loess was improved with 5%cement,the compressive strength increased by 17 times and the tensile strength increased by 12 times.The improvement effects are signif icant.The inf luences of water content and compaction on the strength of the remolded loess are the same as the inf luence on the improved loess.But the effects of water content and compaction on the strength properties of remolded loess are more signif icant.