The vault settlement is leaded almost by excavation of the upper bench and lower center bench in the situation of shallow burial of ⅱ - class rocks ;

在Ⅱ类围岩浅埋条件下，拱顶下沉主要是由 上 台阶的开挖及下台阶中央区的开挖所引起；

The key procedure is excavation of the upper center bench for ⅳ - class rocks ;

对Ⅳ类围岩， 上台 阶开挖为施工的关键工序；

Values of ground surface settlement during upper bench cutting occupy total settlement values among 60 % ~ 70 % in the construction of bench cut method ;

台阶法施工中， 上台 阶开挖引起的地表沉降量占由开挖引起的总地表沉降量的60%～70%之间；

The vault settlement is leaded almost by excavation of the upper bench in adjacent rock above ⅲ - class ;

在Ⅲ类以上围岩条件下，拱顶下沉绝大部分是由 上 台阶的开挖所引起；

Computing results show that the maximum range of influence on the settlement and horizontal displacement is within 3 meters before and after the designated section and magnitudes account for two-third of gross amount ; and the influence of upper bench excavation is obviously greater than that of lower bench ;

计算结果表明：对沉降和水平位移影响最大的是在指定段前后各3m的范围内，约占其总量的2/3，而 上 台阶开挖的影响又明显大于下台阶开挖；

The results show that the key procedure is excavation of the upper and lower center bench for ⅱ - class and ⅲ - class rocks ;

结果表明：对于Ⅱ、Ⅲ类围岩， 上台 阶及下 台阶 中央区的开挖为施工的关键工序；

The establishment of this pattern will play a directly important role in high yield culture of wheat 8539 and new upper bench about wheat of Sichuan .

模型的建立，对小麦8539的高产栽培和四川小麦 上新 台阶具有重要的指导作用。

The excavation of upper chamber was conducted by the methods of bench excavating in layers and common explosion .

上室开挖采用分层 梯 段开挖和普通爆破方法。

Simulation of Limit Displacements for Tunnel Upper Bench

隧道 上 台阶极限位移计算模拟

In addition the plastic zone in surrounding rock ranges 1.5 m in the front of an excavating face and rock bolts are mainly influenced by the excavation of the upper bench in the current construction step .

围岩塑性区位于开挖面前1.5m范围内，锚杆主要受本施工段 上 台阶开挖的影响。