复合岩层中滚刀旋转切割破岩效率试验研究

TBM掘进经常遇到复合岩层,在该地层中施工对滚刀破岩非常不利。为了提高掘进效率,降低工程造价,开展复合岩层滚刀破岩效率研究很有必要。鉴于此,采用滚刀岩机作用综合试验台对砂岩、花岗岩复合(复合比例为4(25) 6)而成的岩层进行5组刀间距下3种贯入度的3把滚刀同步旋转切割试验;试验过程中监测破岩总法向力、总扭矩,并分别收集两种岩石的岩渣进行筛分、称重;依据试验结果分析不同刀间距、贯入度下的法向力、扭矩及比能的关系。研究表明:不同刀间距时,平均法向力、平均扭矩随贯入度的增加而增大但两者的增加趋势不同,即平均法向力随着贯入度的增加几乎呈直线增大,而平均扭矩随着贯入度的增加其递增趋势减小;不同贯入度下存在不同的最优刀间距;砂岩、花岗岩切割轨迹长度比例为4:6时刀间距与贯入度的比值在14左右,破岩效率最高。

Experiments on the efficiency of rock fragmentation by rotary cutting in composite rock strata

The composite rock strata is highly detrimental to the cutters of tunnel boring machines (TBMs) during the tunneling construction. To improve the tunneling efficiency and reduce the construction cost, it is necessary to study the efficiency of composite rock fragmentation by TBM cutters. In this study, the rock breakage experiments were carried out on the specimens of the sandstone and granite composite (composite ratio of 4:6). A series of rotary synchronous cutting tests was conducted on three cutters with three penetration depths at five cutter spacings. During the experiments, the total normal force and total torque of the rock fragmentation were monitored, and slags of two rock types were separately collected for screening and weighing. The relationships between normal force, torque, and specific energy under different cutter spacings and penetration depths were analyzed. The results showed that the average normal force and the average torque increased with the increase of the penetration depth under different cutter spacings. However, their increase trends were different, which meant that with the increase of the penetration depth, the average normal force increased almost linearly, while the average torque increased slowly. In addition, the optimal cutter spacing varied at different penetration depths. It was found that the efficiency of rock fragmentation was the highest when the ratio of cutter spacing to penetration depth was about 14, and the cutting length ratio of the sandstone to granite was 4:6.