the maximum principal stress

基本解释

In region(1), the maximum principal stress is tensile stress;
在拱底应力区，最大主应力为拉应力；
While direction of previous main faults that intersect the maximum principal stress by minor angle also probably becomes the major migration direction of oil and gas.
与最大主应力小角度相交的先期主要断裂的方向也可能成为油气运移的主要方向。
When the tunnel axis is consistent with the fault strike and the vertical stress is the maximum principal stress, it is likely to lead to the tunnel rock cracking, collapse and other damages.
此外，巷道轴线与断层走向一致并且地应力以铅直应力为最大主应力时，最容易引起断层滑移活化导致巷道围岩产生开裂、塌方等破坏。
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最大主应力
The Maximum principal stress equal to Vertical stress approximately, which makes an angle of about 11.9°to 14.25°with the shaft axis.
最大主应力约等于竖向应力，与井筒轴向夹角为11．9°～14．25°。