砂岩泥岩互层地质隧道变形分析及控制技术研究

Study on Deformation Analysis and Control Technology of Tunnelsin Sandstone and Mudstone Interbedding

玉磨铁路是我国云南连接东南亚各国的重要通道,云南地区地质条件复杂、围岩破碎、节理发育、岩质较软,极易发生隧道大变形。针对以上问题,文章基于会岗山隧道变形侵限的工程背景研究合理有效的支护措施。首先通过现场变形数据与数值计算相校核,得出可反映现场实际情况的计算参数;在此基础上通过改变支护结构厚度与钢架间距来探究合理的初期支护参数;其次通过锚杆受力情况来针对层状围岩进行锚杆非等参布置研究。结果表明:(1)UDEC离散元针对破碎围岩及层状围岩的稳定性计算具有较好的吻合性;(2)增加喷射混凝土的厚度或减小钢架间距可明显减小结构变形,但当喷射混凝土较厚时减小钢架间距对结构变形影响不明显;(3)锚杆在与结构面相交时轴力较大,在完整岩块中轴力较小,针对层状围岩锚杆可进行非等参设置。

Yuxi-Mohan railway is an important channel connecting Yunnan province of China with southeast Asian countries.The geological conditions in Yunnan area are complex,the surrounding rock is fractured,the joints are developed,the rock is soft,and the tunnel is prone to large deformation.In view of the above background,this paper studies reasonable and effective support measures based on the engineering background of deformation and support invasion of Huigangshan tunnel.First of all,the calculation parameters that can reflect the actual situation of the site are obtained by checking the field deformation data and numerical calculation;on this basis,the reasonable initial support parameters are explored by changing the thickness of the support structure and the spacing of the steel frame;secondly,the non isoparametric arrangement of the bolts is studied according to the stress situation of the bolts.The conclusions show that:(1)the calculation of UDEC discrete element for fractured surrounding rock and layered surrounding rock has a good agreement;(2)increasing the thickness of shotcrete or reducing the steel frame spacing can significantly reduce the structural deformation,but when the shotcrete is thick,reducing the steel frame spacing has no obvious effect on the structural deformation;(3)when the anchor bolt intersects the structural plane,the axial force is large,while the axial force is small in the intact rock mass,and the rock bolts can be set with non isoparametric parameters aiming at layered surrounding rock.