铁路隧道底鼓段围岩蠕变参数反演方法研究

研究目的:某铁路隧道底部粉砂质泥岩蠕变导致仰拱结构持续底鼓,致使列车降速行驶,对铁路运行造成安全隐患。为较准确获取仰拱底鼓区粉砂质泥岩的蠕变参数,本文基于某隧道仰拱5年多的底鼓变形实际监测数据,建立室内岩石剪切蠕变试验与深度学习(GRNN)相融合的岩体蠕变参数确定方法,并对隧道仰拱蠕变变形进行长期预测。研究结论:(1)铁路隧道底鼓段粉砂质泥岩具有明显蠕变特性,该特性对隧道仰拱持续底鼓变形影响较大;(2)提出了基于深度学习的隧道底鼓段围岩蠕变参数反演方法,该方法结合底鼓段长期监测变形数据,能够有效获取隧底岩体蠕变参数,解决隧道围岩蠕变参数难以确定的难题;(3)反演得到的隧底岩体蠕变参数相应的底鼓变形值与实测值拟合度较高,验证了该方法的合理性;(4)本研究成果可为隧道围岩蠕变参数确定、仰拱蠕变变形预测和底鼓治理提供理论依据。

Research on the Back Analysis Method of Creep Parameters of Surrounding Rock at Floor Heave Section of Railway Tunnel

Research purposes: The creeping of the silty mudstone at the bottom of a railway tunnel caused the continuous floor heave of the invert arch,which caused the train to slow down and caused potential safety hazards to the railway operation. In order to accurately obtain the creep parameters of the silty mudstone in the invert arch floor heave area,based on the actual monitoring data of the deformation of the tunnel invert arch in the past five years,we established a method for determining the creep parameters of rock by combining indoor rock shear creep test with depth-learning( GRNN),and carried out the long-term prediction of tunnel invert arch creep deformation.Research conclusions:( 1) The silty mudstone in the floor heave section of railway tunnel has obvious creep characteristics,which has a great influence on the continuous floor heave deformation of the tunnel.( 2) This paper proposed the creep parameters inversion method of surrounding rock in the bottom heave section of tunnel based on the deep-learning. Combined with the long-term monitoring deformation data of the floor heave section,the creep parameters of the rock mass at the tunnel bottom can be obtained effectively,and the difficult problem of determining the creep parameters of the surrounding rock of the tunnel is solved.( 3) The deformation values of floor heave obtained by inversion agree well with the measured values,which verified the rationality of the method.( 4) The research results can provide theoretical basis for determination of creep parameters of surrounding rock,prediction of creep deformation of inverted arch and treatment of floor heave.