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Chaya County in eastern Xizang was selected as the research area for the susceptibility assessment of geological disasters. Seven evaluation indexes, including elevation, slope grade, slope form, slope direction, slope structure, stratum, and distance from fault, were selected to construct an evaluation model of geological disaster susceptibility using the evidence weight method. Using the annual maximum daily rainfall under four rainfall frequencies (10%, 5%, 2%, 1%) as the dynamic inducing factor and building population and transportation facilities as the hazard bearing body, the dynamic risk of geological hazards in the town was evaluated. The results show that except for the small slopes on both sides of the county town, which were mainly high-risk and extremely high-risk areas, other areas in the research area were mainly medium and low-risk areas. As the frequency of rainfall decreased, the areas of high-risk and extremely high-risk areas increased by a maximum of 5.34% and 0.07%, respectively, while the areas of low-risk and medium-risk areas changed by a maximum of 28.33% and 23.32%, respectively. Based on the risk assessment results, a method for controlling the source of geological hazard risk considering different rainfall frequencies was proposed. Specifically, for the extremely high-risk areas under the four rainfall frequencies of 10%, 5%, 2% and 1%, it is recommended to adopt engineering management, engineering management/professional monitoring, professional monitoring, and professional monitoring/combination of mass monitoring and professional monitoring. For the high-risk and medium-risk areas under a 1% rainfall frequency, the recommended risk control measures were the combination of mass monitoring and professional monitoring, and the combination of mass supervision and mass prevention.The risk management and control system accounted for the dynamic risks of slopes under different rainfall frequencies, which would enhance the management and control of geological hazard risks in mountainous urban areas in a refined manner.

Taking the 23304 knife handle working face of Yungaishan No.2 Coal Mine as the engineering background, the pressure distribution and ground pressure law of the coal around the joint face during the transition from short working face to long working face are studied when the fracture types of the main roof of the working face directly affects the knife handle working face. Theoretical analysis combined with 3DEC numerical simulation was used to analyze the different fracture types and overlying rock structural characteristics of the main roof at the docking stage between No.1 open-off cut and No.2 open-off cut of Yungaishan No.2 Coal Mine, revealing the influence law of different rock beam properties on the range of internal stress field. The results show that the degree of influence of lateral key block B fracture on the coal body is from small to large: the side of the mining area, in front of the coal wall, and directly above the coal wall, the location of the lateral basic top fracture is 6.21 m deep into the coal body, and the internal stress field range is about 12.91-14.43 m. The elastic modulus of the coal body shows a negative correlation and the most significant influence on the internal stress field range.

Waqu, a second-order tributary of the Jinsha River, is located in Gongjue County within the red bed region of Changdu, eastern Tibet. The middle reaches of the basin form a high-mountain canyon zone, serving as a distinctive locus of concentrated rainfall-induced debris flow development area in the county. The density, scale, and activity of debris flow in this area surpass the county’s average level, and the debris flows show a strong correlation with fault structures. Based on field investigation and UAV aerial photography, this paper discusses and scrutinizes the developmental characteristics and principal influencing factors of debris flow within Waqu basin. The findings are as follows: (1) 19 small to medium-scale rainfall-induced debris flows are intensively developed in the middle reaches of the Waqu River, with a development density of 0.84 flows/km, significantly higher than the country-wide average of 0.009 flows/km2. Debris flow on the left bank are characterized by higher development density, drainage area, main channel length, and deposition volume compared to those on the right bank, showing distinct differences in distribution. (2) Debris flow sources on the right bank of the middle reaches are primarily composed of weathered detrital material, distributed throughout the entire watershed. On the left bank, debris flows are dominated by rockslide debris and weathered detrital material, primarily concentrated in the upper and middle reaches of the valley, with a larger overall volume compared to the right bank. The proportion of debris flow sources within the fractured zone of the fault is significant, making it a primary source for debris flows on the left bank. (3) Fault structures are the most significant factor influencing the concentrated development and distinct distribution of debris flows in the middle reaches of the Waqu river, primarily in controlling source conditions. (4) Faults control debris flow source conditions by altering rock mass structure, controlling stratum distribution, modifying microtopography, and changing groundwater conditions, leading to significant differences in source formation rates and volumes between the two banks, which is the fundamental cause of the differential distribution of debris flows.