铁道学报
鐵道學報
철도학보
2014年
9期
79-84
,共6页
既有隧道%浅埋隧道%填土%数值模拟%容许厚度
既有隧道%淺埋隧道%填土%數值模擬%容許厚度
기유수도%천매수도%전토%수치모의%용허후도
existing tunnel%shallow-buried tunnel%filling soil%numerical simulation%allowable thickness
既有浅埋隧道上方填土可能导致其衬砌变形、安全系数降低,甚至发生破坏,危及行车安全。以长枪岭隧道上方某拟建公园填土工程为例,选取若干典型断面,对既有浅埋隧道受不同厚度的填土影响进行数值分析,并确定容许填土厚度。结果表明:既有隧道上方填土将导致衬砌整体下沉,左右两侧沉降基本对称,位移值自上而下逐渐减小;填土后的安全系数降低,但幅度不大,拱脚及仰拱处安全系数偏小,可能出现开裂;既有隧道拱顶位移值随着填土厚度的增加而近似线性增大,为满足位移控制要求,容许填土厚度应为0.3H~0.4H(H 为原覆土厚度)。根据若干断面的分析结果可得整个填土区域的容许填土线,在此范围内进行填土施工,并采取相应的工程措施,既有隧道的运营安全可得到保证。本分析方法简单易行,满足工程精度,可用于指导工程实践,对类似工程有一定的借鉴意义。
既有淺埋隧道上方填土可能導緻其襯砌變形、安全繫數降低,甚至髮生破壞,危及行車安全。以長鎗嶺隧道上方某擬建公園填土工程為例,選取若榦典型斷麵,對既有淺埋隧道受不同厚度的填土影響進行數值分析,併確定容許填土厚度。結果錶明:既有隧道上方填土將導緻襯砌整體下沉,左右兩側沉降基本對稱,位移值自上而下逐漸減小;填土後的安全繫數降低,但幅度不大,拱腳及仰拱處安全繫數偏小,可能齣現開裂;既有隧道拱頂位移值隨著填土厚度的增加而近似線性增大,為滿足位移控製要求,容許填土厚度應為0.3H~0.4H(H 為原覆土厚度)。根據若榦斷麵的分析結果可得整箇填土區域的容許填土線,在此範圍內進行填土施工,併採取相應的工程措施,既有隧道的運營安全可得到保證。本分析方法簡單易行,滿足工程精度,可用于指導工程實踐,對類似工程有一定的藉鑒意義。
기유천매수도상방전토가능도치기츤체변형、안전계수강저,심지발생파배,위급행차안전。이장창령수도상방모의건공완전토공정위례,선취약간전형단면,대기유천매수도수불동후도적전토영향진행수치분석,병학정용허전토후도。결과표명:기유수도상방전토장도치츤체정체하침,좌우량측침강기본대칭,위이치자상이하축점감소;전토후적안전계수강저,단폭도불대,공각급앙공처안전계수편소,가능출현개렬;기유수도공정위이치수착전토후도적증가이근사선성증대,위만족위이공제요구,용허전토후도응위0.3H~0.4H(H 위원복토후도)。근거약간단면적분석결과가득정개전토구역적용허전토선,재차범위내진행전토시공,병채취상응적공정조시,기유수도적운영안전가득도보증。본분석방법간단역행,만족공정정도,가용우지도공정실천,대유사공정유일정적차감의의。
Soil filling above an existing shallow-buried tunnel probably leads to deformation of tunnel lining and reduction of the safety factor and even leads to destroying of tunnel lining and detriment to traffic safety.The filling proj ect of a planned park to be executed above the Changqiangling Tunnel of the Yangpingguan-Ankang Railway was taken as an example.Selecting some typical sections,the influence of different filling thicknesses on the existing shallow-buried tunnel was analyzed numerically and the allowable filling thickness was deter-mined.The research results indicate as follows:Filling above the existing shallow-buried tunnel causes mono-lithic lining settlement and basically symmetrical lining settlement on both left and right sides and produces gradually reduced displacements from vault to invert of the tunnel;the post-filling safety factors of the mono-lithic lining are decreased but by a not-large magnitude,however,the safety factors of the abutment and vauet become so low as to cause cracks possibly to occur;the displacement at the vault increases almost linearly with increasing of the filling thickness,so the allowable filling thickness should be sets as 0.3H~0.4H(H represen-ting the covering depth of the existing tunnel)to control displacements;by analyzing a number of sections,the curve of allowable filling is obtained for the fill zone,then filling within the range of this curve and adoption of corresponding engineering measures can insure the operation safety of the existing tunnel.The proposed meth-od is simple,easy to execute and accurate in meeting engineering requirements,so it can be used to guide engi-neering practice and provide reference to similar engineering proj ects.