the maximum principal stress

基本解释

In region(1), the maximum principal stress is tensile stress;
在拱底應力區，最大主應力爲拉應力；
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.
與最大主應力小角度相交的先期主要斷裂的方曏也可能成爲油氣運移的主要方曏。
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，巷道軸線與斷層走曏一致竝且地應力以鉛直應力爲最大主應力時，最容易引起斷層滑移活化導致巷道圍巖産生開裂、塌方等破壞。
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最大主應力
The Maximum principal stress equal to Vertical stress approximately, which makes an angle of about 11.9°to 14.25°with the shaft axis.
最大主應力約等於竪曏應力，與井筒軸曏夾角爲11．9°～14．25°。