To improve the effectiveness of the directional-predetermined crack blasting in the weak and alternate composite roof, this paper took the coal-containing composite roof of the 12201 working face of Halagou Coal Mine as the engineering background, and based on the technical principles of roof cutting pressure releasing gob-side entry retaining, comprehensive used of theoretical analysis, field experiments and other means, carried out in-depth research on the shaped energy blasting method and parameter design of the coal-containing composite roof. The results show: Through theoretical analysis, in the process of shaped energy blasting, the air column in the hole can reduce the peak blast pressure, which can effectively prevent the weak surrounding rock in the hole from being damaged in the non-cumulative direction and enhance the pre-splitting effect. During detonation at the bottom, the instantaneous pressure in the blast hole is lower than that of detonation at the top, and the action time of blast pressure is longer than detonation at the top. When the buried depth of the explosive (near the blast hole) is less than the critical depth, a “V”-shaped blasting funnel will be formed after the rock blasting, and the critical depth is proportional to the charge. Through field tests on the charge quantity and the length of the sealing mud, when the blast hole depth is 6m, the charge parameters of “3+2+0+1” have a better effect of energy-concentrating blasting, and the crack rate reaches 87%. Besides, field tests have shown that when shaped energy blasting is carried out on soft and hard rock formations, the stemming separation in the shaped energy tube at the interlayer position can ensure the directional pre-cracking effect of hard rock, while effectively avoiding damage to the weak rock formation in the non-cumulative direction.

Through the study of failure mechanisms in soft roadways accompanying by large deformation, their failures are mainly induced by the uncoupling between mechanism of support and rock as well as their strength and rigidity. The deformation starts from key parts and later leads to unstability of the entire support system. Therefore, coupling surrounding rocks and corresponding support is indispensable in terms of the stability in soft roadways. It can be found from a great deal of research and engineering practice that coupling in rigidity between bolts and surrounding rock is able to reinforce rocks to the greatest extent. Coupling in strength, however, is more likely to make its stress field and displacement field evenly distribute. Also, when it comes to coupling in structure, the strength of the surrounding rock can be fully utilized to support roadways. On the basis of engineering surveys and corresponding rock mineral analysis in Hecaogou no. 2 coal mine, it can be found that the major factors causing great deformation in soft roadways are high degree of weathering, quality of surrounding rocks, water penetration and improper support scheme. The surrounding rock is categorized as jointed expandable composite soft rock. And later its deformation mechanism is determined as I AC II BC III CEA, which promotes the new design of net-anchor coupling support for roadway repair.

Based on this, the slope stability and disaster law under the condition of heavy rainfall are studied. With the slope of Shangge Village as the background, the slope stability under the condition of heavy rainfall is deeply studied through theoretical analysis, laboratory physical model experiment, and numerical simulation. Results showed that due to the heavy rainfall within 2 h, the deformation of the slope is not obvious in the rain 2 h~7 h period, first of all in the position of slope toe of slope stress raiser; As the rainfall continued, the infiltration of rainwater led to weakening of the rock mass strength, and the cracks in the slope fracture zone further expanded and extended to the top of the slope. After 7 hours of rainfall, the slope formed a sliding surface. The physical model experiment and the numerical simulation results are in good agreement, which can provide the basis for slope reinforcement under heavy rainfall conditions and have important scientific significance and social value for the reasonable site selection of housing construction, transportation network, and disaster prevention and mitigation in coastal areas.