不同河道形态岸坡抗冲刷能力的三维数值模拟分析

为了研究不同河道形态岸坡的抗冲刷问题,采用轴比λ定义了不同河道形态岸坡:当λ=0时,岸坡坡面形状为平面形;当λ=1/5、1/4、1/3、1/2时,岸坡坡面形状为椭圆形;当λ=1时,岸坡坡面形状为圆形。利用数值软件分析了不同形状岸坡坡角α、坡高h与岸坡抗冲刷能力F之间的关系。结果表明:1对平面形岸坡形状:当h不变时,岸坡抗冲刷能力F随岸坡坡角α的增大而呈现递减变化;当坡角α不变时,抗冲刷能力F随坡高h的增大而呈现递减变化。2对凹形岸坡形状(椭圆形、圆形):当λ、h不变时,岸坡抗冲刷能力F随坡角α的增大而呈现递减变化;当α、h不变时,岸坡抗冲刷能力F随轴比λ的增大呈现先增大后减小的变化。此分析结果可为小浪底库区岸坡形状优化提供参考。     

Radial explosion strain and its fracture effect from confined explosion with charge of cyclonite

Instrumented experiments were conducted in concrete models to study the explosion-induced radial strain and fracture effect of rock-like media under confined explosion with a charge of cyclonite. As a charge was exploded,two different radial strain waves were sequentially recorded by a strain gage at a distance of 80 mm from the center of charge. Through the attenuation formula of the maximum compressive strain(εrmax), the distribution of εrmax and its strain rate(ε) between the charge and gage were obtained. The effect of the two waves propagating outwards on the radial fracture of surrounding media was discussed. The results show that the two waves are pertinent to the loading of shock energy (Es) and bubble energy (Eb) against concrete surrounding charge, respectively. The former wave lasts for much shorter time than the latter. The peak values of εrmax and ε of the former are higher than those of the latter, respectively.     

爆破动荷载作用下围岩累积损伤效应声波测试研究

基于声波测试原理,利用RSM-SY5智能型声波仪,对厂坝铅锌矿某巷道围岩在爆破动荷载作用下产生的累积损伤效应进行了现场试验研究。研究表明:既有开挖爆破对巷道围岩的影响深度为0.8～1.2 m,根据钻孔的深度,在3.5～4.8 m深度的岩体内进行爆破累积损伤效应研究是可行的;随着爆破次数的不断增加,岩体声波速度逐渐降低,损伤度D呈现出非线性累积规律;随着与爆源距离的增大,岩体爆破损伤程度减小,累积损伤效应逐渐变得不明显;水平和垂直方向测试结果存在较大差异,说明爆破作用下岩体损伤具有各向异性的特征。爆破装药位置和药量对岩体损伤累积规律有一定的影响。装药区段范围内的岩体损伤程度最严重,装药量越大,岩体损伤程度也越大。测试成果为进一步的岩体力学参数研究和地下洞室稳定性分析提供了参考依据。     

河南南阳回龙抽水蓄能电站上库渗漏计算水文地质参数的验证

上库特殊的地形、地质条件决定了上库渗漏的严重性,水文地质参数是影响渗漏计算成果的关键因素,勘察设计阶段采用工程类比确定的计算参数可能存在较大误差。工程施工后,根据同一构造带在洞内的渗水情况,选择合理边界条件和概化模型可以反算构造带的渗透系数,反算后的结果表明,原渗漏计算采用的渗透系数是合理的,研究成果为防渗方案的最终确定提供了可靠的依据。     

爆破震动对采空区稳定性影响的FLAC3D分析

针对厂坝铅锌矿受到乱采乱挖破坏的情况,运用FLAC3D对爆破震动作用下采空区的稳定性进行了数值分析。根据现场实测数据,选取了2条不同的实测速度时程曲线作为爆破震动输入,分别进行了静力和动力计算。分析结果表明:(1)采空区开挖后,最大位移量为4.75mm;(2)施加爆破动载荷后,最大位移量增至5.47mm,增幅与爆破震动速度成正比;(3)围岩位移分布的变化受震动波形的影响。爆破震动作用下围岩应力场发生二次重分布,塑性区分布面积明显扩大,采空区右上方露天边坡脚亦受到影响。分析结果与实际观测结果相吻合,并给出了避免爆破震动诱发采空区失稳塌陷的几条建议。     

复杂地质条件下双护盾TBM掘进性能研究

针对复杂地质条件下双护盾TBM的掘进性能问题,以兰州市水源地建设工程输水隧洞双护盾TBM施工为背景,采用现场实测数据统计分析的方法,研究不同地质条件下双护盾TBM利用率、滚刀损耗及掘进速度。研究结果表明：(1)对于Ⅱ类、Ⅲ类、Ⅳ类围岩,TBM利用率随着围岩类别的降低而提高,但Ⅴ类围岩由于易发生涌水及卡机等事故,因此TBM利用率一般低于10%。(2)硬岩对TBM滚刀损耗明显高于软岩,硬岩随着围岩类别的降低,滚刀的损耗明显降低。(3)对于Ⅱ类、Ⅲ类、Ⅳ类、Ⅴ类围岩,随着围岩类别的降低,净掘进速度明显提高,TBM的平均掘进速度受净掘进速度和设备利用率两方面的影响;Ⅱ类、Ⅲ类、Ⅳ类围岩的平均掘进速度随着围岩类别的降低而提高,但Ⅴ类围岩受设备利用率极低的影响,其平均掘进速度最低。     

Catastrophe model and its experimental verification of static loading rock system under impact load

According to the catastrophe model for impact buckling of static loading structures, a new catastrophe model for impact loading failure of a static loading rock system was established, and one dimension （1D） catastrophe model was analyzed. The analysis results indicate that the furcation collection where catastrophe may take place is not only decided by mechanical system itself but also relates to exterior loading, which is different from the results obtained under mono-static loading where the bifurcation collection is only determined by mechanics of the system itself and has nothing to do with exterior loading. In addition, the corresponding 1D coupled static-dynamic loading experiment is designed to verify the analysis results of catastrophe model. The test is done with Instron 1342 electroservo controlled testing system, in which medium strain rate is caused by monotony rising dynamic load. The parameters are obtained combining theoretical model with experiment. The experimental and theoretical curves of critical dynamic load vs static load are rather coincided, thus the new model is proved to be correct.     

探地雷达在厂坝铅锌矿采空区探测中的试验与应用

介绍了探地雷达探测采空区的基本原理及其在厂坝铅锌矿群采空区探测的应用,对其应用效果及存在的问题进行了分析。提出了进一步需要解决的问题和采取的措施。     

Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement

The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation （0.8-1.2 m） was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, hut the damage degree （D） increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers.     

深部巷道失稳的突变理论分析

在考虑围岩力学指标弱化的基础上，运用突变理论探讨了深部巷道失稳破坏的机理；基于势能原理，建立了尖点突变模型，导出了失稳的力学判据务件。结果表明：深部巷道的失稳不仅受岩体特性及所受载荷的影响，而且与围岩中承栽区和松动区的刚度比有关；围岩力学指标弱化程度越高，松动区范围越大，系统失稳的可能性就越大。结合工程实例进行分析，分析结果与实际经验一致，可为预防深部巷道失稳破坏、采取合理措施提供参考依据。