The evolution of mining-induced stress field in longwall panel is closely related to the fracture field and the breaking characteristics of strata. Few laboratory experiments have been conducted to investigate the stress field. This study investigated its evolution by constructing a large-scale physical model according to the in situ conditions of the longwall panel. Theoretical analysis was used to reveal the mechanism of stress distribution in the overburden. The modelling results showed that: (1) The major principal stress field is arch-shaped, and the strata overlying both the solid zones and gob constitute a series of coordinated load-bearing structures. The stress increasing zone is like a macro stress arch. High stress is especially concentrated on both shoulders of the arch-shaped structure. The stress concentration of the solid zone in front of the gob is higher than the rear solid zone. (2) The characteristics of the vertical stress field in different regions are significantly different. Stress decreases in the zone above the gob and increases in solid zones on both sides of it. The mechanical analysis show that for a given stratum, the trajectories of principal stress are arch-shaped or inversely-arched, referred to as the “principal stress arch”, irrespective of its initial breaking or periodic breaking, and determines the fracture morphology. That is, the trajectories of tensile principal stress are inversely arched before the first breaking of the strata, and cause the breaking lines to resemble an inverted funnel. In case of periodic breaking, the breaking line forms an obtuse angle with the advancing direction of the panel. Good agreement was obtained between the results of physical modeling and the theoretical analysis.

长壁板中采动应力场的演化与裂缝场和地层破裂特征密切相关。很少进行实验室实验来研究应力场。本研究通过根据长壁面板的原位条件构建大型物理模型来研究其演化。通过理论分析揭示了覆盖层应力分布的机理。建模结果表明：（1）主应力场为拱形，覆盖在实心区和采空区上的地层构成了一系列协调的承载结构。应力增加区就像一个宏观应力拱。高应力尤其集中在拱形结构的两个肩膀上。料滴前方的实心区的应力集中度高于后方的实心区。（2）不同区域的垂直应力场特征明显不同。料滴上方区域的应力降低，而料滴两侧的实心区域应力增加。力学分析表明，对于给定的地层，主应力轨迹为拱形或反拱形，称为“主应力拱”，而不论其初始断裂还是周期性断裂，并确定了断裂形态。即，在层的第一次破裂之前，拉伸主应力的轨迹是反拱的，并且使断裂线类似于倒漏斗。在周期性断裂的情况下，断裂线与面板的前进方向形成钝角。