The Chinese Journal of Nonferrous Metals
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|第13卷 第11期 总第80期 2016年11月|
(西南交通大学 地质工程系,四川 成都 611756)
摘 要: 某拟建桥位附近地层移动造成桥基岸坡岩体中部分节理面发育成深大宽张裂隙,此类卸荷裂隙往往影响桥基位置的选择,也是桥基荷载下边坡稳定性分析的重点。在现场勘察的基础上,采用赤平投影法分析节理岩体稳定性,确定岩体质量指标,用经验公式结合岩体中宽张裂隙位置确定并修正桥基安全距离。运用离散元和有限元数值模拟深大宽张裂隙及桥基荷载条件下边坡岩体的破坏模式及应力情况,综合分析并验证提出的在安全距离位置桥基荷载条件岸坡的稳定性。研究结果表明,由于裂隙的存在,荷载对裂隙坡前岩体影响不大,但宽张裂隙底部是高应力集中区,将可能导致裂隙再次破坏。在建议的桥位下荷载应力对边坡岩体影响下,桥墩基础是安全的。
（Department of Geological Engineering, Southwest Jiaotong University, Chengdu 611756, China）
Abstract:Some joint surfaces develop into the deep and wide tension fissure in the rock slope of a bridge foundation because of stratigraphic heave. The fissure, one type of stress-release crack contributing to human activity, has a great influence on the determination of the position of bridge foundation and is the focal point to the analysis of rock slope under bridge loading. On the basis of field investigation, the method of stereographic projection was utilized to analyze the stability of the jointed rock mass, and the safe distance of bridge foundation was obtained by calculating the empirical formula involving RMR and fixing that after defining the position of the wide fissures. The failure model and stress regime of the rock mass were analyzed using finite element method and Discrete element method. The rock slope stability of the bridge foundation under the proposed safe distance position was analyzed comprehensively and verified. The analysis results indicate that the front of the rock mass slope is not susceptible to the load for the existence of the wide tension fissures, while the bottom of the fissure is high stress concentration area where it is prone to failure of the rock mass again. The bridge foundation is safe under the proposed position.
Key words: wide tension fissure; rock slope; stability; numerical simulation