基于损伤机制的切槽控制爆破特性研究

通过LS-DYNA的自定义接口,嵌入基于混合应力准则的统计损伤模型,对比分析了常规圆孔和V型切槽的爆破应力与损伤分布特性,分析了V型切槽的存在产生两个力学效应,既在切槽尖端处产生高度拉应力集中,同时切槽孔壁其它部位的应力分布相对减弱;针对切槽角度和切槽深度两个重要参数进行了优选。结果表明,随着切槽角度增大,损伤控制效果呈开口向下的抛物线规律变化,最佳角度为60°左右,切槽深度存在门槛值,在一定范围内切槽深度越大,损伤控制效果越好,但切槽深度超过门槛值后对损伤控制效果的影响不明显;岩体的不同强度对最佳切槽角度和最佳切槽深度取值的影响,不同强度对岩体的最佳切槽角度影响不大,但对最佳切槽深度的影响明显,随着岩体强度的增大,最佳切槽深度变大。

Damage control characteristics for notched blasting based on the damage mechanism

In this paper,based on the secondary development of the LS-DYNA,a user-defined statistical damage model was implemented.The stress and damage distribution of conventional circle hole and notch hole were compared.Results demonstrate that two mechanical effects are induced by the notch.High stress concentration is generated at the edge of the notch and the stress at the other part of blast hole is reduced.The sensitivity analysis of notch angle and depth were carried out.Results reveal that the most perspective angle is 60°.The threshold value of notch depth exists,while the control effect of damage is not obvious when the depth is bigger than the threshold value.The rock strength affects the selection of the best depth significantly.As the rock strength increases,the depth is larger.The research results of this paper have important engineering application value.