多种工况螺纹钢锚杆应力应变特征研究

Stress and strain characteristics of screw-thread steel bolts in different working conditions

针对锚杆应力应变复杂多变、难以准确实测的问题,在开展实验室拉伸测试及DIC监测的基础上,采用数值模拟分析了正常及存在缺陷螺纹钢锚杆在不同工况下杆体应力应变特征及其演化规律。研究结果表明:锚杆杆体最大应力、最大真实应变和最大塑性应变均随着载荷值和载荷类型的增加,总体上呈增大趋势;当锚杆含缺陷时,缺陷部位应力应变明显集中,而缺陷形态、位置等会影响应力应变分布。由于螺纹和横肋等结构以及缺陷的存在,杆体易产生局部应力和应变集中,塑性应变也更大。在高载荷和腐蚀等影响下,塑性应变集中处易发展成为裂纹源头,进而导致锚杆断裂失效。该研究结果可以为锚杆结构优化、状态监测和寿命预测等提供参考价值。

To solve the problems of complicated,unpredictable bolts stress,the stress and strain characteristics and evolution rules of normal and defective screw-thread steel bolts in different working conditions are analyzed by numerical simulation based on laboratory tensile testing and DIC monitoring.The results show that,the maximum stress,maximum true strain and maximum plastic strain of anchor rods increases gradually with the increase of load values and types,generally presenting an increasing tendency.When the bolt has defects,the stress and strain on defects are obviously concentrated,the shape and location of defects will affect the stress and strain distribution.Due to the existence of screw-thread steel,transverse ribbed structures and defects,local stress and strain are concentrated on rods and the plastic strain turns larger.The sites of plastic strain concentration are prone to develop into the source of cracks under the influences of high load and corrosion,which leads to the failure of bolt breakage.The research results can provide a reference for bolt structure optimization,condition monitoring and service life prediction.