| 尹文杰,苏永华*,黎诗诚,肖俊杰,沈嘉铖.静态爆破中炮孔拐角应力集中及导向效应研究[J].实验力学,2023,38(4):530~540 |
| 静态爆破中炮孔拐角应力集中及导向效应研究 |
| Study on stress concentration and guiding effect of borehole corner in static blasting |
| 投稿时间：2022-08-09 修订日期：2022-12-18 |
| DOI：10.7520/1001-4888-22-192 |
| 中文关键词: 静态爆破 正三角孔 定向破裂 裂纹 |
| 英文关键词:static blasting the equilateral triangle hole directional rupture crack |
| 基金项目:国家自然科学基金(52178330)资助 |
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| 中文摘要: |
| 在圆形钻孔中灌装破碎剂进行裂岩，其产生的裂纹通常具有随机性。为实现软岩工程中的定向裂岩，本文采用正三角孔替代传统的圆形钻孔，基于相似原理，选用河砂、水泥、石膏等相似材料模拟软岩，开展双孔静态膨胀的室内试验。以孔间距和孔偏转角作为自变量，探讨不同工况下裂纹的扩展规律以及致裂效果，并建立模型试块的力学模型，进行裂纹对比及扩展研究。试验结果表明：正三角孔具有良好的定向效果，裂纹从孔尖拐角处萌生，并大致沿孔角平分线方向发育扩展；紧靠裂纹处的应变曲线会历经试验初期、起裂前、裂纹失稳扩展和平稳波动4个阶段。孔偏转角存在会抑制裂纹的发育，数值计算表明，在0°~30°范围内，偏转角度越大，裂隙数量越少，对裂纹发展的抑制效果越明显。致裂的破坏模式以受拉破坏为主，剪切破坏为辅；在裂纹附近区域，与裂纹平行方向受压，垂直受拉。 |
| 英文摘要: |
| The process of static expansion and fracturing is generally to fill the cracking agent in the circular drilling hole, and rock is cracked by the expansion and pressure generated by the hydration reaction of the cracking agent. Due to the low tensile strength of the rock, the resulting expansion pressure will destroy the rock. The cracks are often random and cannot be directional. In order to realize directional fracturing in soft rock engineering, in this paper, an equilateral triangular hole was used instead of the traditional circular drilling hole, and the directional fracturing of rock was achieved by using the corner energy accumulation effect of the special-shaped hole. Based on the similarity principle, river sand, cement, gypsum, and other materials were selected to simulate soft rock, and static expansion tests with double holes were carried out in the laboratory. Taking hole spacing l and hole deflection angle as independent variables, the crack propagation law and effects of fracturing were investigated under different working conditions. The mechanical numerical model of the test block was established. Then the crack propagation was compared with the laboratory test and further propagation studies were carried out. Experimental results show that using of the equilateral triangular hole has a better directional effect than the general round hole. The crack initiates from the sharp corner of the hole and develops along the bisector of the hole angle roughly. The strain curve close to the crack goes through four stages: the initial stage, pre-crack stage, crack instable propagation stage, and steady fluctuation stage. The existence of the equilateral triangular hole deflection angle can inhibit crack development. Numerical calculation shows that the larger the deflection angle, the fewer cracks and the more obvious inhibition effect of crack development in the range of hole deflection angle 0°~30°. Tensile failure is the main failure mode and shear failure is the secondary failure mode. In the area near the crack, the compression is parallel to the crack and the tension is vertical. |
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