为研究软岩巷道在不同水平应力边界条件下底鼓变形失稳规律，以贯屯煤矿50213工作面回风巷为工程背景。根据软岩巷道底板破坏特征，运用压杆理论建立软岩巷道底板结构力学模型，通过力学分析，确定了底板失稳的判别条件及临界应力的计算方法，并采用底板岩层变形的挠曲方程推导得出底鼓量计算公式。通过相似模拟确定了不同应力状态下底板破坏机理及裂隙的动态演化过程，提出锚杆-混凝土组合结构控制底鼓的方法并应用于现场实践。研究结果表明：当加载至3.13 MPa时，巷道两侧形成应力集中区，并通过两帮传递至底板，剪切裂隙沿巷帮围岩内部发育至底板内部，该裂隙距两帮0.8 m，发育角度约45°。当加载至4.38 MPa时，底板在水平应力作用下向巷道临空面弯曲变形，底板中部产生拉伸裂隙。当应力加载至7.70 MPa时，底板破坏深度增加至1.2 m，裂隙数量增多，由于底板各分层挠度不同易产生离层裂隙，各裂隙相互贯通并向深部延伸，最大底鼓量为0.51 m，与理论计算结果基本一致。50213工作面回风巷底鼓主要是由底板岩性和应力集中所致，因此提出了以锚杆-混凝土组合结构来控制底鼓的防治措施，试验段观测结果表明，16 d后底鼓平均速率趋于稳定，最大底鼓量为0.153 m，较未支护时减少73%，底板控制效果较好，验证了支护参数的有效性。

In order to study the regularity of floor heave deformation and instability of soft rock roadway under different horizontal stressboundary conditions, the return air roadway of 50213 working face of Guantun Coal Mine was taken as the engineering background. Accordingto the failure characteristics of floor in soft rock roadway, the mechanical model of floor structure in soft rock roadway is establishedby using the pressure bar theory. Through mechanical analysis, the distinguishing conditions of floor instability and the calculationmethod of critical stress are determined, and the calculation formula of floor heave is derived by using the deflection equation of floor rockdeformation. The failure mechanism of floor and the dynamic evolution process of cracks under different stress states were determined bysimilarity simulation, and the floor heave control method of rock-concrete composite structure was put forward and applied in field practice.It can be concluded that when the loading is 3.13 MPa, the stress concentration zone is formed on both sides of the roadway and transferredto the floor through the two sides. The shear fracture develops from the interior of the wall rock along the roadway wall to the interiorof the floor. The fracture is 0.8 m away from the two sides and the development Angle is about 45°.When loaded to 4.38 MPa, the floorbends and deforms towards the roadway surface under the action of horizontal stress, and tensile cracks occur in the middle of the floor. When the stress is loaded to 7.70 MPa, the failure depth of the floor increases to 1.2 m and the number of cracks increases. Due to the differentdeflections of each layer of the floor, it is easy to produce stratification cracks, and the cracks are connected with each other and extenddeep. The maximum floor heave is 0.51m, which is basically consistent with the theoretical calculation results. 50213 face return airroadway floor heave is mainly caused by the rock and stress concentration, thus put forward the concrete combination with anchor rodstructure to control the floor heave prevention measures, experimental section observation results show that the average speed of floorheave of 16 days tend to be stable, the sole drum quantity is 0.153 m, is not supporting to reduce 73%, floor control effect is better, Thevalidity of supporting parameters is verified.