排序方式: 共有44条查询结果,搜索用时 31 毫秒
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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。 相似文献
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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. 相似文献
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岩渣是TBM掘进过程中岩机作用的直接产物,其粒径分布规律是进行TBM地质适应性、掘进效率和刀具消耗评价的重要指标。针对刀具消耗评价问题,结合兰州水源地建设工程输水隧洞双护盾TBM施工,对TBM在不同岩体条件中掘进时产生的岩渣进行了现场量测与筛分试验,并对实测岩渣粒径分布数据进行了统计分析和理论分布函数拟合。对TBM掘进过程中刀具消耗规律进行了分析总结,探讨了不同岩体条件下TBM刀具消耗规律与岩渣粗糙度指数、岩渣颗粒级配系数以及岩渣粒径分组比例等参数之间的相关关系。研究结果表明:①刀具消耗与岩体地质条件密切相关,岩石强度越高,耐磨性越强,刀具消耗越大,Ⅱ类和Ⅳ类围岩中TBM刀具消耗明显高于Ⅲ类围岩;滚刀直径对刀具消耗有一定影响,采用大直径滚刀可降低同等围岩条件下的刀具消耗;②不同岩性条件下岩渣粒径分布不均匀,总体上属于级配良好,符合Rosin-Rammler函数,可采用Rosin-Rammler函数进行岩渣粒径分布参数计算;③刀具消耗与岩渣曲率系数的相关性不明显,与不均匀系数存在较好的二次函数关系,相关系数为0.875;④刀具消耗与岩渣粗糙度指数存在较显著的二次函数关系,相关系数为0.8... 相似文献
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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。 相似文献
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爆破震动对采空区稳定性影响的FLAC3D分析 总被引:19,自引:3,他引:19
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。 相似文献
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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。 相似文献
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Catastrophe model and its experimental verification of static loading rock system under impact load 总被引:1,自引:1,他引:1
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. 相似文献
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Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement 总被引:2,自引:0,他引:2
闫长斌 《中南工业大学学报(英文版)》2007,14(2):230-235
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. 相似文献