含软弱夹层顺倾边坡爆破层裂效应的数值模拟与试验研究

Numerical simulation and test of lamination effect caused by blasting in layered rock slope with weak intercalated layer

进行含软弱夹层顺倾边坡单孔爆破数值模拟,分析爆破过程中上覆岩体受到的应力作用、爆破层裂效应及其对边坡稳定性的影响。模拟结果表明,爆破层裂作用具有分区特性,爆轰气体对夹层的冲刷、推移作用形成夹层爆腔区,爆腔区外围是压密区,其次是离析区,离析区以外的夹层未受爆破层裂作用的影响;上覆岩体在空腔区受到爆轰气体膨胀压力作用,临近夹层壁面的峰值压力达0.75 GPa,压密区受到夹层挤压衍生的向上压力作用,压力峰值达0.21 GPa,且压力衰减较慢;空腔区的上覆岩体与夹层脱离,压密区和离析区改变了夹层与上覆岩体的接触状态,使模型的稳定性降低。剪切试验验证了数值模拟关于爆破层裂效应降低模型稳定性的结论。

Numerical simulation of single hole blasting in layered rock slope with weak intercalation is carried out;then analyses of stress effect of the rock mass overlying,lamination effect caused by blasting and its affect on the slope stability are conducted.The simulation results that lamination effect has zoning characteristics.Blasting cavity region is formed by explosive gas scouring and lapsing the weak intercalation,the regions out of blasting cavity region are tightness region and segregation region.The weak intercalation out of segregation region is not effected by lamination effect.The rock mass over cavity region is subjected to expansion pressure from explosive gas,the peak pressure of rock mass adjacent to the interlayer wall reaches to 0.75 GPa;the tightness region is subjected to upward pressure derived from squeezing of interlayer,the peak pressure reaches to 0.21 GPa;and the pressure attenuation is relatively slow.The stability of model is decreased by the detachment of rock masses from weak intercalation and tightness region,and segregation region changes the contact state.The lamination effect which decreases the stability of model is testified by shear test.