【作者】 孟建；

【导师】 李新平；

【作者基本信息】 武汉理工大学 ， 岩土工程， 2010， 硕士

【摘要】 对于竖井工程的施工开挖,最常采用的手段仍然是钻孔爆破法。岩石一混凝土材料在爆破冲击作用下的断裂破坏问题是一个非常重要的问题。爆破施工在完成岩体开挖的同时,不可避免地对井筒周围衬砌及岩体产生不利影响。井井筒衬砌是混凝土,爆破振动作用下可能导致混凝土与岩体胶结面脱离或者导致混凝土强度下降,使得衬砌效果降低,甚至失去效用。在爆炸产生的应力波作用下,混凝土衬砌会发生剥离现象。周围岩石介质损伤,原有裂隙的贯穿,新裂隙的产生与扩展,从而导致力学性质的劣化。当爆破振动达到一定强度后,有可能导致局部处于临界受力状态的竖井边墙岩体或混凝土衬砌发生局部坍塌和失稳,从而导致安全事故的发生。论文通过对溪洛渡水电站左岸出线竖井开挖爆破的振动速度现场测试,运用萨道夫斯基公式对测试数据进行了回归分析,得到了竖井爆破掘进中地震波传播衰减公式,运用衰减公式预测最高处测点速度,并与实测数据进行对比,结果显示竖井爆破振动存在高程放大效应,水平振速放大系数约为1.49～2.24,垂直振速放大系数约为1.78-2.73,相对高差越大,放大系数越大。高程对爆破振动波的放大效应明显。爆破振动速度还受到衰减效应,二者相互作用,爆破振动速度放大系数随高程增高而增大,当增加到一定临界值时,衰减因素占主要因素时,放大系数不再随高程增加而增大。通过对萨道夫斯基公式进行修正,得到考虑高程因素的衰减公式,修正公式线形关系显著,可以对存在高程放大效应的爆破振动速度进行预测。根据考虑高程的修正公示反求得到安全允许最大段药量,进而对爆破网络重新优化设计,降低爆破振动效应。运用动力有限元分析方法,对竖井结构在爆炸冲击波荷载作用下的结构响应进行数值模拟,对比数值模拟结果与现场测试结果。研究表明：相对高差不大时,数值模拟结果与实测结果整体趋势比较吻合,距离爆心0～15m,振动速度快速衰减,振动速度峰值衰减幅度超过总体幅度的60%,距离爆心超过30m,衰减不超过总幅度的10%。采用岩石一混凝土强度破坏准则对竖井构筑物在爆炸冲击荷载作用下的稳定性进行强度校核,为竖井后续施工安全提供安全判据。更多还原

【Abstract】 The most common method used in shaft excavation was still drilling and blasting. Fracturing of rock and concrete materials under blasting impact was a very important issue. Concrete lining and rock around of the shaft was subjected to negative impact while complete the excavation of the shaft. The cement surface of rock and concrete may separated and the strength of concrete may decreased under blasting vibration effect, and the lining effect may drop or even useless. The concrete lining would peel off under blasting wave. The damage of surrounding rock and the original fracture run through and the generation and expansion of the new fracture may lead to the deterioration of mechanical properties. When the blasting vibration reaches certain intensity, it may lead to shaft wall rock or concrete lining which was at critical stress state partially collapse or instability, even lead to the occurrence of accidents.By field test on cable shaft of Xiluodu Hydropower Station, Regression analysis according to Sadaovsky empirical formula were using. The seismic wave propagation attenuation was obtained. Use the attenuation formula to forecast the vibration velocity of the highest measured point. Compare the Predicted value with the measured data, Result have shown that there is elevation amplification in shaft blasting vibration. The Magnification factor of Horizontal direction was 1.49～2.24,and the vertical direction was 1.78～2.73. The greater of the relative height, the magnification factor is larger. It was obvious of the blasting vibration wave amplification effects with elevation increase. Blasting vibration velocity is also subject to attenuation effects, the interaction between the two, blasting vibration velocity amplification factor increased with the increase of elevation, as to a certain critical value, the attenuation factor accounting for the main factor, the magnification factor no longer increases with elevation. With Sadaovsky empirical formula amended, attenuation formula was got which consider of the elevation factors, the linear relationship of corrected formula was significantly. It can predict blasting vibration velocity which has elevation amplification factor. The maximum security section of quantity of explosive was obtained according to corrected formula, and then re-optimizing the design of the blasting network, reducing blasting vibration effect.Dynamic FEM was used to simulate the blasting effect of the shaft. Shaft structures respond to the action of the blasting seismic wave was analyzed. The regression results were compared with the simulation results. Studies have shown that the numerical simulation results trends was fit with the regression trends when the relative height difference is not significant. The vibration velocity was attenuating fast between 0～15 meters, more than 60% of overall vibration velocity was attenuated. Less than 10% of overall vibration velocity was attenuated at 30 meters out of the blasting center. Strength failure criterion was used to check the stability of the shaft, and a reference for the safety of the following construction was provided.更多还原