大柳塔煤矿地下水库人工坝体一般由挡水坝墙和一个与其平面垂直的支撑墙组成，坝体结构稳定可靠但强度富余系数过大，因而存在可优化的空间。挡水坝墙承载性能主要与其骨架结构和厚度有关，由于其骨架结构的等效配筋率已接近规范要求的最小值，因此可通过改变其厚度来进行坝体结构优化。利用正交异性板模型对坝墙在水压与上覆垂直载荷共同作用下的极限承载性能进行了分析，结果表明:随着上覆垂直载荷的不断增大，坝墙极限水头值会不断减小，坝墙稳定性会由外表面强度控制逐渐转变为由内表面强度控制，且该变化的转折点出现的时间受坝墙厚度影响，坝墙厚度越小，转折点出现的时间越早;若在水库服务期间，水库储水水位一直保持不变且上覆垂直载荷不断增大，则坝墙内外表面会先后发生破坏，且其破坏的先后次序会受水库储水水位的影响，当水库储水水位高于转折点对应的极限水头值时，则坝墙内表面先发生破坏，外表面后发生破坏，反之则坝墙内表面先发生破坏，外表面后发生破坏;储水水位越低，坝墙表面发生破坏所需的时间越长，坝墙的长期稳定性越好;根据大柳塔煤矿地下水库日常储水高度及坝墙上覆垂直载荷的变化范围，得出现有人工坝体结构中的支撑墙可去除，且其中的坝墙厚度可减小至0.6~0.7 m范围内，从而节省材料，提高坝体建设经济性。

The artificial dam body of underground reservoir in Daliuta Coal Mine is composed of a retaining dam wall and a supporting wall perpendicular to retaining dam,and the dam structure is stable and reliable. However,the margin coefficient of the structure strength is too high,there is room for the dam structure to be optimized. The carrying capac- ity of retaining dam wall is mainly related to its skeleton structure and thickness. Since the equivalent reinforcement ra- tio of the dam skeleton structure is close to the minimum required by the specification,the structure of dam can be op- timized by changing the thickness of retaining dam wall. The ultimate carrying capacity of the retaining dam wall under the impact of water pressure and overlying vertical stress was analyzed by the orthotropic plate model. The analysis shows that with the increase of overlying vertical load,the limit head value of dam wall will decrease continuously,the stability of dam wall will be controlled by external surface strength first,then gradually by internal surface strength. The time when the variation turning point occurs is affected by the thickness of dam wall,the thinner the wall is,the earlier the turning point appears. If the water level in reservoir remains unchanged and the overlying vertical load increases continuously during the service period of the reservoir,the internal and external surfaces of the dam wall will be dam- aged successively,and the priority of damage of internal and external surface of the dam is affected by the water level in the reservoir. When the water level in reservoir is higher than the limit head corresponding to the turning point,the damage of external surface is earlier than the internal surface,and vice versa. The lower the water level in reservoir is, the longer it takes for the dam wall to break,and the better the longer-term stability of dam wall is. According to the daily water storage height of underground reservoir and the variation range of vertical load on the dam wall in Daliuta Coal Mine,it can be concluded that in the existing structure of the artificial dam,the support wall can be removed,and the thickness of the dam wall can be reduced in range from 0. 6 m to 0. 7 m,thus saving material and enhancing the economy of dam construction.