A translational landslide comprised of nearly horizontal sandstone and mudstone interbeds occurred in the Ba River basin of the Qinba–Longnan mountainous area. Previous studies have succeeded to some extent in investigating the formation mechanism and failure mode of this type of rainfall-induced landslide. However, it is very difficult to demonstrate and validate the previously established geomechanical model, owing to lack of landslide monitoring data. In this study, we considered a translational landslide exhibiting an unusual morphology, i.e., the Wobaoshi landslide, which occurred in Bazhong, China. First, geological conditions of this landslide were determined through field surveys, and the deformation and failure mode of the plate-shaped main bodies were analyzed. Second, long-term monitoring was performed to obtain multiparameter monitoring data (width of the crown crack, rainfall, and accumulated water pressure in cracks). Finally, an equation was developed to evaluate the critical water height of the multistage bodies, i.e., h_cr, based on the geomechanical model analysis of the multistage main sliding bodies, and the reliability of this equation was verified using long-term relevant monitoring data. Subsequently, the deformation and failure mode of the plate-shaped bodies were analyzed and investigated based on numerical simulations and calculations. Thus, the monitoring data and geomechanical model proved that the accumulated water pressure in cracks makes cracks open much wider and causes the plate-shaped bodies to creep. Simultaneously, an optimized monitoring methodology was proposed for this type of landslide. Therefore, these research findings are of reference significance for the rainfall-induced translational landslides in this area.

The working environment in hot dry rock boreholes, encountered in deep geothermal investigation drilling and ultra-deep geological drilling (up to 5000 m), is very difficult at the present stage. We have developed a drilling trajectory measuring instrumentation (DTMI), which is based on the interference fiber-optic gyro (FOG). This can work continuously, for 4 h, in an environment where the ambient temperature does not exceed 270 ^∘C and the pressure does not exceed 120 MPa. The DTMI is mainly divided into three parts: an external confining tube, a metal vacuum flask, and a FOG measurement probe. Here, we focus on the mechanical design, strength, and pressure field simulation analysis for the external tube, the structural design and temperature field simulation analysis for the vacuum flask, and the FOG Shupe error analysis and compensation in the temperature field. Finally, through the engineering applications of the SK-2 east borehole of the China Continental Scientific Drilling (CCSD) project and the geothermal well of Xingreguan-2, the data measurements of the drilling trajectory were used to analyze the stability of the DTMI. The instrument realizes long-duration, high-stability work in the process of making trajectory measurements in an ultra-deep hole. The instrument has the characteristic of anti-electromagnetic interference and enables work to be carried out in the blind zone of existing technologies and instrumentation. Therefore, DTMI has great potential in the promotion and development of geological drilling technology.

Internal thrust force of unstable rock and soil mass is an essential parameter for prediction of many geological hazard. Currently, fiber bragg grating (FBG) and optical time-domain reflectometer (OTDR) are widely used to measure internal stress of unstable rock and soil mass. However, these methods have disadvantages such as low spatial resolution and the paucity of distributed measurements. This paper develops a quasi-distributed thrust measurement system based on an optical frequency domain reflectometer (OFDR). Firstly, we design an optical fiber stress sensor head using the characteristics of the optical fiber microbending effect. And then, the cubic spline interpolation method is used to compensate for the nonlinear effects of the OFDR. Finally, we implement a laboratory experiment of lateral stress to make error calibration. As a result, the OFDR sensing system achieved a spatial resolution of 20 cm by using a 500 m test fiber, maximum measurement pressure reached 1.059 MPa and relative error is 8.9%. We implemented OFDR in the Chenjiagou landslide located at the Three-Gorge of Chongqing in China. The results showed that this system can accurately locate six fiber stress sensors within the landslide over a range of 0 ∼ 420 m, obtaining the lateral thrusts as well.

The multidimensional and multi-sliding surface measurement of deep-seated displacement on landslides poses a significant technical challenge in landslide monitoring and early warning. The fixed-borehole inclinometer serves as an important measurement method based on drilling for this purpose. In this study, a novel flexible measurement array for deep-seated landslide displacement and its installation and measurement processes were developed, enabling higher accuracy in full-hole multidimensional deformation measurement. The measurement array consists of individual measurement probes as basic units, connected in series through coaxial cables and high-pressure rubber hoses, forming a flexible measurement array. Each probe is equipped with acceleration and magnetic field sensors, allowing for the measurement of borehole inclination and azimuth angles and providing a more comprehensive understanding of the deformation of deep-seated landslides. This flexible measurement array resolves the limitations of traditional fixed inclinometers, such as limited probe quantity or inaccurate installation positions that fail to reflect the deformation trend of the landslide body. Moreover, it eliminates the need for auxiliary installation accessories like pulleys and inclinometer pipes, simplifying the mechanical structure and installation process, which represents an advancement in methodology and an improvement in measurement techniques. This array provides a more comprehensive and improved monitoring tool for disaster prevention and mitigation, thereby enhancing the level of geological hazard monitoring and early warning technology.

Suffered from the unsatisfied time consumption of thermal error compensation, this paper aims to realize a faster and more accurate fibre optic gyroscope (FOG) thermal error compensation plan, so that the deep‐hole inclinometer using in mining which is based on FOG will make accurate measurement under external thermal field. Using uniform mixed‐data design method, it is learned that the temperature compensation experiments only consumed 1/9 the time required for traditional method within the working condition range of 0~120°C. Suffice it to say that our method can markedly enhance the efficiency of FOG temperature compensation. To this end, the finite‐element method (FEM) was also applied to explore the thermal conductivity and simulate the complex boundary conditions of the FOG. Then, the Shupe error of the FOG was calculated and used to derive the FOG error compensation formula, and the factors and their levels affecting the Shupe error in thermal field were considered in error compensation experiments. After that, the optimal design of FOG thermal error compensation experiments was created by FOG error compensation formula and uniform mixed‐data design table, and this plan significantly reduced the number of experiments compared to before. Finally, the design was compared with the full‐scale design and orthogonal design to verify its accuracy and efficiency. The comparison shows that the proposed method can markedly enhance the efficiency of FOG error compensation and elevate the measuring accuracy of FOG. This paper innovatively applies the uniform mixed‐data design method to the field of FOG measurement, and this research offers new insights into the error compensation optimization of FOG measurement.

For the sake of collecting deep seawater samples automatically and promoting unmanned marine environmental monitoring technology level, a deepwater sample collection for unmanned catamaran is designed. The seawater sample collection system is designed based on the data of the catamaran stability analysis model. The system can be analyzed respectively into four parts, including an auto-telescopic holding mechanism, a wire rope arranging mechanism, a double-body unmanned surface vehicle(USV) and a water docking diversion mechanism. Based on the classification, the internal components of the system are subjected to force analysis calculation and three-dimensional modeling by software, and the finite element analysis is conducted on the key points of the device. Therefore, the deep seawater samples collection system can meet the automatic deepwater collecting demand of USV under the influence of environmental factors such as wind, sea waves and surges.