小凈距隧道爆破施工對鄰近裂縫隧道動力響應(yīng)的影響

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[ABSTRACT]Inorder to studythedynamic response lawof adjacent lining crack tunnelsduring blasting constructionof small clearance tunnels，numerical simulationmethodswereusedtostudythe efectof diferentdistribution positiosand depthsoflining cracks indiffrentlevelsofrockonblastingdynamicresponse.Theresultsshow thatthediffrentdistribution positions and depthsof lining cracks indiferent levelsofrock have no significantimpactonthevibration velocityresponseof the lining of existing tunnels.Butthere isacertain impact onthestressresponseof thelining of existing tuels. Theimpact isonlynearthecracksand varies withthedistribution positions，sizes，androck levels.Whenthere are cracks indiferentpositionsofthliningofexisting tunnels，thereisacertainamplificationefectonthetensilestressofthestructure.Theamplification efect is most significant when there arecracks inthe sidewallsfacing theexplosion.Atthe same position ofthe lining of the existing tunnel，thedeeper thecracks，thegreater thenearbyprincipal tensile stress.The higherthelevelof therock，the more significanttheamplificationeffectoftheprincipaltensile stress nearthecrack.When using vibration velocityas the safetycontrol benchmarkfor adjacent cracked tunnelsduringthe blasting construction process of newtunnels，thecontrol valueof vibration velocityatthecrack locationshouldbeappropriatelyreduced，andthedegree of reduction varies with the distribution position and depth of the crack.

[KEYWORDS]smal clear distance tunnel; blast； reconstruction and expansion； crack； dynamic response

0 引言

近年來，隨著經(jīng)濟建設(shè)的快速發(fā)展，我國城市化建設(shè)不斷向前推進，現(xiàn)有的道路交通運輸能力已經(jīng)無法滿足日益增長的交通運輸量[1]。（剩余8739字）