层状盐穴难溶夹层爆破效应数值模拟研究

Numerical simulation on the blasting of insoluble interlayer in bedded salt cavern

难溶夹层控制爆破可消除层状盐穴建腔隐患、加强建腔速度。为研究层状盐穴难溶夹层爆破效应,采用带围压的分离式Hopkinson压杆(SHPB)装置开展了泥岩夹层动态力学特性试验,获得了泥岩夹层的塑性随动硬化模型参数,嵌入LS-DYNA有限元程序进行了模拟验证,建立了层状盐穴难溶夹层爆破数值模拟模型,揭示了不同炸药当量及药柱位置对夹层爆破垮塌范围以及盐腔密闭性的影响规律。研究结果表明:在LS-DYNA中采用塑形随动强化模型可以较好地拟合泥岩夹层动力特性;作用于盐腔围岩应力波通过卤水和夹层岩体两种介质传递,应力波在岩体中传播的速度明显大于在水中传播的速度;在本计算实例中选取药柱半径7.5cm,高度6m,炸药当量76.8kg,并布置在夹层中部可促使夹层可控垮塌,并保证盐穴围岩的密闭性。

The controlled blasting of insoluble interlayer can eliminate hidden dangers in the cavity construction and speed it up.In order to study the blasting effect of insoluble interlayer in bedded salt cavern,the dynamic mechanical properties of mudstone interlayer were tested by the split Hopkinson pressure bar (SHPB) device with confined pressure,and the parameters of a plastic-kinematic model were obtained.The LS-DYNA finite element program was embedded in the simulation verification,and the numerical model for the bedded salt cavern insoluble interlayer blasting was established.The influences of different explosive equivalent at different explosive positions on the collapse range of interlayer blasting and the tightness of salt chamber were revealed by the numerical simulation model.The results show that the dynamic characteristics of mudstone can be well fitted by using the plastic-kinematic model in LS-DYNA.The stress wave acting on the surrounding rock of salt chamber is transmitted through the brine and interbed rock mass.The velocity of stress wave in rock mass is obviously faster than that in water.In the case,of the column radius 7.5 cm,height 6 m,explosive equivalent 76.8 kg,the interlayer can be controlledly collapsed when the explosive is put in the middle of the interlayer,and the closeness of the surrounding rock of the salt cavern is ensured.