大瑞铁路澜沧江大桥工程边坡稳定性三维数值模拟分析

3D NUMERICAL SIMULATION OF SLOPE STABILITY OF LANCANGJIANG BRIDGE ON DALI-RUILI RAILWAY

采用现场调查、工程地质分析和三维数值模拟方法,对在建大瑞铁路工程澜沧江大桥边坡稳定性进行了综合分析研究。澜沧江大桥是在建大瑞铁路的控制性工程之一,由于多种因素的综合作用,桥址岸坡发育延伸较长的顺坡向节理和近垂直的陡倾节理。右岸桥位工程开挖区位于一组较大型顺坡结构面的下方,岸坡稳定性直接关系到桥位的适宜性。综合研究表明,工程开挖后,右岸桥位上部岩体极易在顺坡向结构面的控制下发生滑移–拉裂式破坏,沿外倾结构面产生较大的位移,甚至可能失稳,需要进行专门的工程治理。左岸边坡岩体结构相对稳定,工程开挖后,位移将主要集中在开挖面附近的浅表层部位,不仅变形较小,影响范围也相对较小。

The Lancangjiang Bridge is one of the controlled engineerings on the under-construction Dali-Ruili Railway.Along the bank slopes at which the bridge site is located there are greatly developed long-extending dip-slope joints and nearly vertical joints,The excavation area of the bridge site on right bank is below a group of large dip-slope structural planes,so the slope stability is directly related to the suitability of bridge site.Comprehensive studies show that excavation on right bank will be like to induce slip and tension crack failure affected by the dip-slope structural planes and to cause great displacement along extraversion structural planes,and even instability on whole slope,with which the specialized engineering management should be taken to deal.On the contrary,rock masses on left bank are of a relatively stable structure,and the displacement induced by engineering will mainly take place on shallow surface of excavation site,with slight deformation and limited influence area.