Although regional geohazard risk assessment has been carried out for many years, due to the difficulty in evaluating and quantifying the risk of geohazards, and the difficulty in investigating and obtaining data from risk elements, the quality of regional risk assessment has always been low, and research progress has been slow. In addition, the natural conditions of the northern Tibetan Plateau are harsh, with high cold and anoxic conditions, and many peaks covered by glaciers. Most areas are rarely visited, and the level of research is extremely low, the basic geological data and research results on geohazards are relatively scarce, and the risk assessment of regional geohazards is close to blank, making it difficult to meet the needs of local governments for geohazards reduction, prevention, and emergency management. This paper takes Bangor County of Nagqu City, Tibet Autonomous Region as the research area. Using remote sensing image data from GF-1 and GF-2 in 2020 and 2021, as well as GIS technology, the number, types, scales, developmental characteristics, and distribution laws of geohazards within a 2.8×104 km2 area of Bangor County are identified. Information volume method is used to systematically carry out high-precision and large-scale risk assessment of geohazards throughout the county. The susceptibility, hazard, vulnerability and risk of geohazards in the entire county are comprehensively evaluated. The study shows that due to its location on the Qinghai-Tibet Plateau and sparse population, the overall level of geohazard risk in Bangor County is not high, with 98% of the area being low-risk zones. Medium and high-risk zones are mainly concentrated around towns. These evaluation results provide scientific basis for reducing and preventing geohazards in Bangor County.

Settlement observations are important means to verify the soft soil and guide the design and construction of ground.In this paper,field settlement observations and differential settlement after the soft soil treatment in the section of K42 +400~K42 +500 of Arongqi to Boketu highway have been analyzed.It is showed that settlement occurred mainly in filling period.Distribution of settlement along the base cross-section is uneven.It is verified after the treatment of sand cushion + geogrid,the transverse differential settlement can be reduced and the bearing capacity of foundationgood can be improved.

Many explanations were proposed for the deformation mode of the bank slope.The geological background of Three Gorges was introduced generally at first,and then the unique deformation phenomenon of the slope was serib.Through comprehensive study,it was pointed out that the unique deformation mode of the slope was controlled by the unique structure of the slope.The slope consisted of nearly horizontal layer,with soft layer and hard layer interbedded and perpendicular joints well developed.The strata outcropped in the slope were the second formation and the third formation of Badong group,which belong to middle Triassic system(T).The second formation of Badong group(T2b2) was purplish-red mudstone,which was vulnerable to weather and disintegration,and the third formation of Badong group was brittle and vulnerablion to dissolution.These characteristics of the strata led to deeply remoulding of the structure of the rock mass in the slope,and induced collapse of the structure of the rock mass.Thus,the slope took on some phenomena like slide or slump,and made the deformation mode of the slope complicated.