散粒体中的锚杆加固效应规律及作用机理分析

Laws of anchoring effect with anchor bolts in granular mixtures and analysis of acting mechanism

针对散粒体锚固效应数值模拟存在的不足,通过试验设置多组参数,并对加锚散粒体结构施加荷载,以稳定后散粒体散落质量比例表征结构强度,探究不同因素对锚固效应的量化影响,同时深入分析了其作用机理.试验结果表明,适当增大散粒体的粒径、缩小锚杆间距或提高锚杆承托圆盘面积占结构底面积的比例都能够在一定程度上提升结构强度;考虑3种变量的共同影响,令变量J为粒径与锚杆间距之比乘以锚杆承托面积比,当J>0.15时结构强度已至最大,同时避免了材料的消耗;此外,增加锚杆所受预应力大小也能有效提高锚固强度,但当预应力达到某一临界值,继续增加预应力大小对提高强度的作用效果不再明显.

In light of the several existing drawbacks in numerical simulation consequences of granular anchoring effect, this paper establishes multiple groups of parameters through essential experiments in which the land is applied on the anchored granular structure. Representing structural strength with the proportion of fallen granular mixtures after the structure achieves stability; this paper explores quantitative influence of distinct factors on anchoring effect and profoundly analyzes anchorage mechanism. Experimental results reveal that properly broadening particle size, diminishing anchor spacing and elevating supporting area ratio of anchor bolts are, at some extent, able to augment structural strength. Considering mutual in- fluence of three variables, this paper introduces a variable J equaling the rate of particle size and anchor spacing multiplies by supporting area ratio of anchor bolts. When J is greater than 0. 15, structural strength will reach the highest level simultaneously avoiding wastes of materials. Moreover, amplifying prestress can also obviously promote anchoring strength. Nonetheless, when the prestress overpasses a certain critical value, constant increase of prestress will not effectively enhance strength any longer.