【摘要】 顶效隧道位于岩溶发育地区,地质构造复杂,岩体破碎,对超前预报技术的要求高,风险较大。目前国内外应用的隧道超前预报技术多数都存在着技术缺陷,不能区分不同方向的地震回波,不能准确地确定掌子面前方围岩的波速,不能正确地进行纵横波分离等问题,影响到预报的可靠性和准确性。为了确保施工安全,减少和避免地质灾害发生,顶效隧道超前预报中采用了TST技术。应用结果表明,TST技术采用空间阵列系统和速度扫描技术有效地解决了掌子面前方围岩速度分布问题,提高了构造定位精度;应用二维方向滤波技术有效地消除了上下、左右的侧向回波和面波干扰,成功提取了前方回波用于超前预报,避免了虚报误报,解决了复杂地质条件下的超前预报问题。更多还原

【Abstract】 Dingxiao Tunnel is located at the karsts area in Guizhou province;in which the geological structure is very complicated and full of crushing rocks.All these bring high risk in tunnel excavation;and its tunnel geological prediction work faces great difficulty.Currently there are several tunnel geological prediction techniques,but most of them have three major issues.First,they did not differentiate the echo seismic waves from individual directions;it assumes all the seismic waves come from the front tunnel face.Second,they can not calculate the rock velocity in the front tunnel face.Third,they cannot separate p wave and s wave correctly.So the result cannot be accurate and reliability.For safety and efficiency,a new tunnel geological prediction technique,the tunnel seismic tomography(TST) is adopted in Dingxiao tunnel.TST utilizes spatial observation,F-K filtering and velocity scan techniques which solved all the issues indicated above.The function of spatial observation and velocity scan in TST gives precise velocity analyzing and enabled accurate geological structure locating.The F-K filtering function of TST gets rid of the surface wave and sidewise echo wave,only uses the wave coming back from front.更多还原