在役边坡耐久性弱化及整体稳定性影响分析

Weakening of Durability and Overall Stability of an In-Service Slope

针对在役边坡长期耐久性能弱化及对整体稳定性影响问题,首先依据混凝土结构耐久性原理,建立边坡支护结构耐久性弱化分析模型,结合室内耐久性加速试验进行验证分析,接着基于混合型非连续变形分析法(HDDA)扩展了锚杆单元连接不同位移模式块体的算法,利用该扩展型混合DDA法结合有限元法以分析耐久性弱化边坡稳定性问题,建立了总体计算基本框架。最后以浙江省某沿海公路边坡为案例进行分析,结果表明:在特定环境条件下边坡多型支护结构物在30~60 a内有锈胀开裂及断裂失效的可能性;假定锚杆不失效时边坡安全系数随年限增加存在一定降幅,而在考虑锚杆陆续失效时边坡安全系数降幅明显,需要提前采取加固措施。此外还表明混合型DDA法建模灵活、模拟结果合理,具有较好的应用价值。

The impact of the weakened long-term durability performance on the stability of in-service slopes was studied.Initially,a mechanical performance degradation model was developed for slope support structures based on the classical durability principle of concrete structures.This model was validated using results from indoor durability accelerated tests.Subsequently,the algorithm for anchor elements connecting blocks with different displacement modes was investigated and expanded based on the Hybrid Discontinuous Deformation Analysis(HDDA) method.Utilizing this HDDA method in conjunction with the finite element method for comparison,a computational framework for analyzing weakened in-service slope stability was established.By applying the aforementioned method,a case study involving a highway slope in Zhejiang Province was conducted.The findings revealed that,under given environments,the slope support structures may experience rusting,cracking,and eventual fracture failure within30-60 years.Assuming that the ultimate bearing capacity of anchor rods remains intact,the slope safety coefficient decreases over time.Taking into account the progressive durability deterioration and fracture of the anchor rods,there is a significant reduction in the slope safety coefficient,necessitating preemptive reinforcement measures to meet safety requirements.Furthermore,the results highlight the flexibility of the HDDA method in modeling and achieving reasonable outcomes,indicating its potential for further practical applications.