It gives the scientific voice way of horizontal crustal stress by gravity. 给出了重力所致水平地应力的科学表达方式。
Vertical stress makes rock stratum reforming voussoir beam, horizontal in-situ stress is the main source to cause the voussoir beam crushed. 竖直方向地应力使顶板岩层形成铰接拱结构，水平地应力是拱铰压碎的主要力源。
