昔格达层高填方路堤沉降变形特性研究

Research on the Deformation Properties of Xigeda Layer High Fill Embankment

研究目的:新建的攀枝花南站车站路堤填筑高度达到36 m,出于地质、地形条件限制和经济考虑,该处的高填方路堤工程的填料拟采用路堑开挖的昔格达层土,但受其成因机制、物理力学特性、构造条件及地下水等因素的影响,昔格达土工程性质极差,易产生不同程度的地质灾害。本文以成昆线攀枝花南站昔格达层高填方路基工程为依托,利用ABAQUS软件建立三维整体有限元模型,分析昔格达层高填方路堤在分层填筑过程中的沉降变形规律,从而为实际工程建设提供参考。研究结论:(1)昔格达地层为极软岩,产状平缓,具有水稳性差、透水性弱的特性;(2)在合理控制施工质量,做好排水措施的情况下,昔格达土可作为路堤填料使用;(3)昔格达层高路堤在分层填筑过程中,最大变形位置发生在填筑体高度的1/2h～1/3h处;(4)昔格达层路堤和路基表面的最大沉降量都随填方高度的增长而增长,路基的最终工后沉降量为4.2 cm,最大沉降速率为3.99 cm/a,基本满足规范的要求;(5)本研究成果对我国西南山区类似工程地质条件下的铁路、公路等工程建设具有借鉴意义。

Research purposes： The embankment embankment filling intends to adopt the Xigeda height of the new Panzhihua soil due to the geological, South railway station reaches 36 m and the topographical and economic considerations. However, affected by its formation mechanism, physical and mechanical properties, structural conditions and groundwater, the engineering properties of Xigeda soil is very poor, and it is easy to produce different geological disasters. Based on the engineering of Panzhihua South railway station, a three - dimensional finite element model was established using ABAQUS, and the settlement and deformation of the subgrade in the stratified filling process was analyzed, which can provide reference for the practical construction. Research conclusions： （ 1 ） The Xigeda strata is extremely soft rock, the dip angles of rock formation is gentle, with the characteristics of poor stability of water and weak permeability. （2） Under the conditions of the strict control of construction quality and drainage measures, the Xigeda strata can be used as the embankment filling material. （3） The maximum deformation position of the high embankment in the stratified filling process occurs at 1/2 h - 1/3 h of the height of the filling body, which agrees with the actual. （4） The maximum settlement amount of the embankment and subgrade surface of Xigeda strata increases with the increase of the filling height. The final post - construction settlement of the subgrade is 4.2 cm and the maximum sedimentation rate is 3.99 cm/a, which meet the demands of the specification.（5） The results of this paper can be used for reference in the construction of railway and highway under the similar engineering geological conditions in the southwest mountain area of China.