Safety status of artificial slopes is significant for the operation and maintenance of highway to mitigate the risk; thus, slope hazard identification is necessary. In order to realize large-area and low-cost application for regional highway, taking the Longqing Highway (length of 55 km) as a case study, the SBAS-InSAR (Small Baseline Subset-Interferometric Synthetic Aperture Radar) technique is adopted to detect the ground deformation and conduct hazard identification based on slope dip, aspect, geological data and historical hazard record. Field survey is carried out to verify the identified potential hazards. Results show that the detected potential hazards are distributed mainly in the areas consisting of granite residual and the Quaternary soil. Six potential hazards identified by the SBAS-InSAR-based method are roughly in accordance with the on-site verification. It is suggested that the SBAS-InSAR technique has the ability to obtain the slope deformation accurately and reveal the safe condition of the slopes. The SBAS-InSAR technique can be suitable for assistance in regional highway slope inspection.

Soil‐rock mixture is a common filling material for earth dam and subgrade. In this study, research concerned on the evolution law of engineering characteristics of soil‐rock mixture under different factors and the effect of defect on subgrade strength, and geotechnical tests were carried out to analyze the influence of different factors on engineering characteristics of soil‐rock mixture in the study, and the physical model was carried out to analyze the effect of different compaction works on the resilient modulus, and the influence of defect on the strength was explored by manually preset loose body. The test results showed that (1) when the soil‐rock mixture was graded, P = 78, the moisture content was 14%, and the engineering characteristics were optimal; (2) there was a positive correlation between compaction times and resilient modulus, and the stress transferred from the subgrade to soil was linearly distributed under the good condition of compactness; and (3) the existence of loose body not only reduces the modulus of resilience but also affects the stress transfer; the larger the loose body, the lower the resilient modulus and the greater the stress transfer.

Oujiang River North Estuary Bridge in Wenzhou is the world’s first double‐deck suspension bridge under construction with three‐tower and four‐span. It is the first time to build large open caisson foundation in the deep marine soft clay in estuary with strong tide, extending the application scope of caisson. To study the deformation and stress characteristics of large open caisson during excavation and ensure the safety of anchorage excavation, a large number of sensors are arranged in the caisson. By analyzing the change of tip resistance, lateral soil pressure, and posture parameters during caisson excavation, the stress characteristics and deformation of caisson are described. The result shows the following. (1) Because of the thixotropy of soft clay, the reaction force of partition wall in deep soft soil area of caisson is similar to that of blade foot, and the reaction force of blade foot can be effectively reduced through the layering construction of caisson. (2) The height of caisson construction and the sand‐bearing stratum will obviously affect the plane torsion angle of caisson. When the caisson enters the sand‐bearing stratum, the lateral soil pressure increases significantly, which leads to the increase of the plane torsion angle. (3) The inclination and central deviation of caisson are sensitive to the caisson construction and stratum property. It can be found that the lateral soil pressure, plane torsion angle, inclination, and central deviation of caisson are sensitive to stratum property, and inhomogeneity of stratum easily leads to inclination of caisson. Based on the field monitoring data, the stress characteristics and geometric posture of caisson during sinking are studied, which provide technical guidance for scheme design and subsidence prediction analysis of caisson in deep marine soft clay. It can provide a good opportunity to study the behaviors of large caisson foundation constructed in deep marine soft clay and has great significance and reference value for construction optimization of anchorage structure.

As one of the common geological disasters on the seafloor, the occurrence of pockmarks often indicates the existence of submarine fluid. And the formation of the pockmarks is generally attributed to the soil carried away by the fluid. The research established physical model test and found: (1) The pockmark formed after aeration, and particle gradation changed in the center area of the pockmark where coarse particle (particle size/0.25 mm) increased obviously and fine particle (particle size ≤0.075 mm) decreased significantly; (2) Comparing the volume of the pockmark with the volume of the soil extracted by siphon, it can be found that the volume of the pockmark was much larger than the loss of soil, and the difference reached its peak when the inflation pressure was 20 kPa; (3) Comparing the cone resistance of the soil in the surface and boundary, it can be found that the resistance of the center and marginal soil was much bigger than the outside, and the cone resistance of the boundary was also improved greatly. The research considered that the formation of pockmark was not only related to the soil being carried away by the bottom current, but also the consolidation by vibration existed.

The decomposition of gas hydrates releases gas and water at volumes much larger than the original volume. The gas escapes violently, which destroys seabed sediments and can even cause geological disasters. To explore the effect of natural gas hydrate decomposition on underwater slopes, laboratory experiments were conducted to observe the features of slope failure. Aeration was used to model the gas that was produced by hydrate decomposition, and the results were as follows. (a) Once air filled into the bottom of the underwater slope, the pore pressure at the slope was altered, which eventually caused the slope to fail. (b) The formation of pockmarks corresponded to the variations in the pore-water pressure. (c) The theoretical analysis results showed that the sedimentation rate of fine particles (d < 0.4 mm) was lower than the water flow velocity, indicating that these particles were carried away with the air–liquid two-phase flow, which eventually caused the pockmarks to develop into craters.