水–力耦合模型下干湿循环作用对新旧路基沉降的数值模拟研究

陈刚¹，李浩¹，孙恩赐²，宋修广²，袁志明¹，庄培芝^2*，杨汝东²

1.葛洲坝集团交通投资有限公司，湖北 武汉  430033；2.山东大学齐鲁交通学院，山东 济南  250002

摘要：为分析降水和地下水位交替升降等因素影响下路基填土的饱和状态的变化以及承载与变形特性，对考虑水–力耦合及滞回效应的非饱和土本构模型进行二次开发，采用数值模拟分析干湿循环作用下高速公路拓宽工程中新旧路基的沉降规律。结果表明：整体上路基沉降随路表含水量增大或地下水位的上升而增大；路表含水率变化引发的干湿循环时，路基产生不可逆的永久沉降，且单次循环导致的沉降随循环次数增加而减小。路基拓宽宽度对沉降分布具有调控效应，主要表现为新填路基部位的沉降差异显著，旧路基中心处的沉降差异较小。

关键词：路基拓宽；非饱和土；干湿循环；数值模拟

Numerical simulation study on the settlement of new and old roadbeds under the action of dry-wet cycles in a water-force coupling model

CHEN Gang¹, LI Hao¹, SUN Enci², SONG Xiuguang², YUAN Zhiming¹, ZHUANG Peizhi^2*, YANG Rudong²

1. Gezhouba Group Transportation Investment Co., Ltd., Wuhan 430033, China;

2. School of Qilu Transportation, Shandong University, Jinan 250002, China

Abstract: Under the influence of rainfall and alternating groundwater levels, the saturation state of subgrade soils is prone to significant changes, resulting in different bearing and deformation characteristics. By the secondary development of the constitutive model of unsaturated soil considering hydro-mechanical coupling and hysteresis effects, numerical simulations were conducted to analyze the settlement law of new and old sungrade in expressway widening projects under drying-wetting cycles. The results indicate that the settlement of the subgrade increases with the increase of surface water content or the rise of groundwater level. The drying-wetting cycles caused by changes in the water content of subgrade surface can generate the irreversible permanent settlement. With the number of cycles increases, the permanent settlement generated by a single cycle decreases. The width of new subgrade will influence the settlement of the whole subgrade. Under different widening widths, the difference of settlement in the center of the old subgrade is not significant, while the difference of settlement at the new subgrade is significant.

Keywords: subgrade widening; unsaturated soil; drying-wetting cycle; numerical simulation