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特长深埋隧道岩爆倾向性预测与影响因素研究

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岩爆倾向性预测是深埋硬岩隧道工程施工的难点,以往研究多以隧道施工中现场监测数据为预测基础,但预测结果存在时效性和局限性.从西南地区某特长深埋隧道工程区地应力现场实测数据出发,对区域地应力场进行三维数值反演分析,获取隧道轴向地应力特征,从而对隧道施工中岩爆倾向性等级进行预测,并利用数值模拟手段对岩爆影响因素进行对比分析,其结果可为类似特长深埋隧道工程提供参考.研究结果表明:①实测点附近三向主应力总体趋势为:σH>σv>σh,其中最大水平主应力σH值为10.96~17.07 MPa,方向N9°W~N7°E;②隧道轴向最大水平主应力σH最大值为23.88 MPa,最小水平主应力σh较恒定;竖向主应力σv最大值为46.70 MPa,其量值变化和隧道埋深呈正相关.该隧道具备岩爆发生的基本条件,施工中存在中等、强烈岩爆风险;③侧压系数为0.8时,墙角处岩爆倾向性较大,其他各部位倾向性相同;埋深越大,岩爆倾向性越大,且各部位岩爆倾向性受埋深的影响程度基本一致;围岩弹性模量为40 GPa时,岩爆倾向性最大;围岩内摩擦角大于40°时,隧道断面各部位岩爆倾向性趋于平稳.
Prediction of Rockburst Tendency and Study of Influencing Factors in Extra-Long Deep-Buried Tunnels
Rockburst tendency prediction is a challenge in the construction of deep-buried hard rock tunnels.Previous studies have mainly relied on on-site monitoring data from tunnel construction,but these predictions are limited by their timeliness and scope.Based on the field-measured data of geo-stress from an extra-long deep-buried tunnel engineering area in Southwest China,a three-dimensional numerical inversion analysis of the regional stress field was conducted to obtain the axial stress charac-teristics of the tunnel.This enabled the prediction of rockburst tendency levels during tunnel construc-tion.Numerical simulation methods were used to compare and analyze the influencing factors of rock-burst.The results can serve as a reference for similar extra-long deep-buried tunnel projects.The re-search results showed that:(1)The overall trend of the three-direction principal stress near the mea-surement point was σH>σv>σh,with the maximum horizontal principal stress σH ranging from 10.96~17.07 MPa,oriented at N9°W~N7°E.(2)The maximum horizontal principal stress σH in the tun-nel was 23.88 MPa,while the minimum horizontal principal stress σh was relatively constant.The ver-tical principal stress σv reached 46.70 MPa,and its variation was positively correlated with the tun-nel′s burial depth.The tunnel met the basic conditions for rockburst occurrence,with moderate to strong rockburst risk during construction.(3)When the lateral pressure coefficient was 0.8,the rock-burst tendency was higher at the wall corners,while other locations exhibited similar tendencies.The greater the burial depth,the higher the rockburst tendency,and the impact of burial depth on rock-burst tendency was generally consistent across different locations.When the elastic modulus of the sur-rounding rock was 40 GPa,the rockburst tendency was the largest.When the internal friction angle of the surrounding rock exceeded 40°,the rockburst tendency across the tunnel section became stable.

deep-buried tunnelrockburst predictiongeo-stress field inversioninfluencing factors

陈贤丰、李德武、刘金松

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中铁二院工程集团有限责任公司,四川 成都 610031

兰州交通大学土木工程学院,甘肃 兰州 730070

深埋隧道 岩爆预测 地应力场反演 影响因素

国家自然科学基金项目中国铁路兰州局集团有限公司科技研究开发计划

518680382020-41

2024

防灾减灾工程学报
中国灾害防御协会 江苏省地震局

防灾减灾工程学报

CSTPCD北大核心
影响因子:0.529
ISSN:1672-2132
年,卷(期):2024.44(5)