水泥搅拌桩桩体性能劣化对盐渍软弱土路基沉降影响研究

Study on influence of deterioration of cement pile on settlement of salted soft soil subgrade

为研究盐渍软弱土路基地区水泥搅拌桩桩体水泥土劣化规律及对路基沉降影响,设计了盐溶液干湿循环制度,并进行了5种不同配合比水泥土在5、15、20次盐溶液干湿循环作用后的无侧限抗压强度测试。结果表明,在干湿循环5次时,由于盐溶液中硫酸盐的结晶膨胀填充作用和对矿物掺合料的激发作用,使水泥土更加密实,强度提高;但采用普通硅酸盐水泥作为固化剂的配合比出现强度降低。随着盐溶液干湿循环次数增加,所有配合比的水泥土强度均出现降低。在试验基础上采用软件模拟计算水泥土劣化对路基沉降的影响,结果显示,水泥搅拌桩土体强度劣化程度与路基沉降呈线性关系。配合比1、2在盐溶液干湿循环20次后仍能保证路基在列车静、动载作用下满足沉降要求。

In order to study the deterioration rules of cement-soil of cement mixing pile in saline soft soil subgrade area and its influence on the settlement of subgrade, the salt solution dry-wet circulation system is designed, and the unconfined compressive strength of cement-soil with 5 different mix proportions is tested after 5, 15 and 20 salt solution dry-wet cycles. The results show that due to the crystallization, expansion and filling effect of the sulfate in the salt solution and the excitation effect on the mineral admixture, the cement soil is more compacted and the strength is improved after 5 dry-wet cycles. With the increase of the number of salt solution dry-wet cycles, the strength of the cement-soil of all mix ratios decreased. On the basis of experiment, software is used to simulate the influence of soil cement degradation on subgrade settlement. The results show that the degree of soil strength degradation of cement mixing piles is linearly related to subgrade settlement. For mixing ratio 1 and 2, the roadbed can meet the settlement requirements under the static and dynamic loads of the train after 20 salt solution dry-wet cycles.