Automatic landslide identification by Dual Graph Convolutional Network and GoogLeNet model-a case study for Xinjiang province, China

Landslides are a natural disaster that exists widely in the world and poses a great threat to human life and property, so it is of great importance to identify and locate landslides. Traditional manual interpretation can effectively identify landslides, but its efficiency is very low for large interpreted areas. In this sense, a landslide recognition method based on the Dual Graph Convolutional Network (DGCNet) is proposed to identify the landslide in remote sensing images quickly and accurately. The remote sensing image (regional remote sensing image) of the northern mountainous area of Tuergen Township, Xinyuan County, Xinjiang Province, was obtained by GeoEye-1 (spatial resolution: 0.5 m). Then, the DGCNet is used to train the labeled images, which finally shows good accuracy of landslide recognition. To show the difference with the traditional convolutional network model, this paper adopts a convolution neural network algorithm named GoogLeNet for image recognition to carry out a comparative analysis, the remote sensing satellite images (single terrain image) of Xinyuan County, Xinjiang Province is used as the data set, and the prediction accuracy is 81.25%. Compared with the GoogLeNet model, the DGCNet model has a larger identification range, which provides a new method for landslide recognition of large-scale regional remote sensing images, but the performance of DGCNet is highly dependent on the quality and characteristics of the input image. If the input data quality is poor or the image structure is unclear, the model’s performance may decline

The characteristic and size–frequency distribution of rocks at the Zhurong landing site, Mars

The rock characteristic and size–frequency distribution (SFD) on Mars are important for understanding the geologic and geomorphic history of the surface, for evaluating the trafficability of roving, and for planning the potential infrastructure construction. Tianwen-1, China’s first autonomous Mars exploration mission, formed an excavated depression during touchdown, which has been the deepest depression on the Martian surface so far compared with others. According to the images captured using the Navigation and Terrain Cameras (NaTeCams) onboard the rover, Zhurong, the SFD of rocks is calculated and compared inside the excavated depression, within and out of the blast zone. For the first time, the rock size distribution inside the excavated depression is obtained, exposing the geological features of the shallow subsurface on Mars at a depth of tens of centimeters, which will surely be important for future drilling missions. It is found that the rock abundance in the depression is smaller than the original abundance on the surface, and the distribution of rocks in the blast zone on the surface is greatly influenced by the touchdown. In addition, based on the fractal dimension of rock sizes, the rocks (>10 mm) at the shallow subsurface of the Zhurong landing site may experience two different geological processes

Geomechanical Studies on Granite Intrusions in Alxa Area for High-Level Radioactive Waste Disposal

Geological storage is an important concept for high-level radioactive waste (HLW) disposal, and detailed studies are required to protect the environment from contamination by radionuclides. This paper presents a series of geomechanical studies on the site selection for HLW disposal in the Alxa area of China. Surface investigation in the field and RQD analyses on the drill cores are carried out to evaluate the rock mass quality. Laboratory uniaxial and triaxial compressive tests on the samples prepared from the drill cores are conducted to estimate the strength properties of the host rock. It is found that the NRG sub-area has massive granite intrusions, and NRG01 cored granite samples show the best rock quality and higher peak strength under various confinements (0–30 MPa). NRG01 granite samples are applied for more detailed laboratory studies considering the effects of strain rate and temperature. It is observed that the increasing strain rate from 1.0 × 10−5–0.6 × 10−2·s−1 can lead to a limited increase on peak strength, but a much more violent failure under uniaxial compressive tests on the NRG01 granite samples, and the temperature increasing from 20 °C–200 °C may result in a slight increase of UCS, as well as more ductile post-peak behavior in the triaxial compressive tests

Failure Behavior of Granite Affected by Confinement and Water Pressure and Its Influence on the Seepage Behavior by Laboratory Experiments

Failure behavior of granite material is paramount for host rock stability of geological repositories for high-level waste (HLW) disposal. Failure behavior also affects the seepage behavior related to transportation of radionuclide. Few of the published studies gave a consistent analysis on how confinement and water pressure affect the failure behavior, which in turn influences the seepage behavior of the rock during the damage process. Based on a series of laboratory experiments on NRG01 granite samples cored from Alxa area, a candidate area for China’s HLW disposal, this paper presents some detailed observations and analyses for a better understanding on the failure mechanism and seepage behavior of the samples under different confinements and water pressure. The main findings of this study are as follows: (1) Strength reduction properties were found for the granite under water pressure. Besides, the complete axial stress–strain curves show more obvious yielding process in the pre-peak region and a more gradual stress drop in the post-peak region; (2) Shear fracturing pattern is more likely to form in the granite samples with the effect of water pressure, even under much lower confinements, than the predictions from the conventional triaxial compressive results; (3) Four stages of inflow rate curves are divided and the seepage behaviors are found to depend on the failure behavior affected by the confinement and water pressure

Study on the Progressive Failure Characteristics of Longmaxi Shale under Uniaxial Compression Conditions by X-ray Micro-Computed Tomography

To investigate the deformation-failure process of Longmaxi shale under uniaxial compression conditions from the mesoscopic and macroscopic points of view, novel X-ray microComputed Tomography (micro-CT) equipment combined with unique loading apparatus was used. Cylindrical shale samples (4 mm in diameter and 8 mm in height) were produced to perform a series of uniaxial compression tests. CT scanning images at different time points during the loading process were obtained to study the characteristics of the progressive failure. In addition, stereograms were reconstructed and vertical slices were selected to explain the failure mechanism. From the results of the testing the low-density area, local per-peak cracks, numerous post-peak cracks and secondary cracks consecutively appeared in the CT images. Vertical and inclined fissures in the samples could be observed from the stereograms’ surfaces and from internal slices. The cracking indicates that the failure process of shale is progressive and the failure mechanism of shale under uniaxial compression is mainly tension destruction or comprehensive tension-shear destruction

Phenomenology of plume–surface interactions and preliminary results from the Tianwen-1 landing crater on Mars

The plume–surface interaction (PSI) is a common phenomenon that describes the environment surrounding the landers resulting from the impingement of hot rocket exhaust on the regolith of planetary bodies. The PSI will cause obscuration, erosion of the planetary surface, and high-speed spreading of dust or high-energy ejecta streams, which will induce risks to a safe landing and cause damage to payloads on the landers or to nearby assets. Safe landings and the subsequent scientific goals of deep-space exploration in China call for a comprehensive understanding of the PSI process, including the plume flow mechanics, erosion mechanism, and ejecta dynamics. In addition, the landing crater caused by the plume provides a unique and insightful perspective on the understanding of PSI. In particular, the PSI can be used directly to constrain the composition, structure, and mechanical properties of the surface and subsurface soil. In this study, we conducted a systematic review of the phenomenology and terrestrial tests of PSI: we analyzed the critical factors in the PSI process and compared the differences in PSI phenomena between lunar and Martian conditions; we also reviewed the main erosion mechanisms and the evolution and development of terrestrial tests on PSI. We discuss the problems with PSI, challenges of terrestrial tests, and prospects of PSI, and we show the preliminary results obtained from the landing crater caused by the PSI of Tianwen-1. From analysis of the camera images and digital elevation model reconstructions, we concluded that the landing of Tianwen-1 caused the deepest crater (depth > 40 cm) on a planetary surface reported to date and revealed stratigraphic layers in the subsurface of Martian soil. We further constrained the lower bounds of the mechanical properties of Martian soil by a slope stability analysis of the Tianwen-1 landing crater. The PSI may offer promising opportunities to obtain greater insights into planetary science, including the subsurface structure, mineral composition, and properties of soil

Effect of Ge doping on the magnetic properties of Fe-6.5Si soft magnetic composites

In this work, the effect of Ge content on the soft magnetic properties and microstructure of FeSiGe soft magnetic powder cores (SMPCs) was systematically investigated. The results show that the addition of Ge is beneficial to increase the electrical resistivity of Fe93.5-xSi6.5Gex SMPCs, and the coercivity (Hc) shows a trend of decreasing and then increasing with the increase of Ge content. When the content of Ge is 2 wt%, the SMPCs exhibit the best magnetic properties with stable effective permeability of 78.4 up to 1 MHz, low core loss of 589.5 mW/cm3 at a maximum magnetic induction of 0.1 T and frequency of 50 kHz. By doping with Ge, the micro-vortex dots in the magnetic domain structure are reduced and the domain walls move more easily with the applied field, and the magnetic properties are improved

Triaxial fluid depressurization experiments with different shut-in strategies on a granodiorite sample

This is the experimental data for the manuscript entitled Fluid extraction mitigates post-injection seismicity in laboratory experiments and geothermal reservoirs, which has been submitted for consideration for publication in Nature.The files include the recorded and computed data of the laboratory-scale fluid depressurization experiments presented in the manuscript. "Hydraulic_data.xlsx" is the injection and monitoring data of the injected distilled water derived from the Quizix Q6000-20K pumps. "Mechanical_data.xlsx" is the raw data recorded by the MTS-815 rock mechanics testing system as well as the stress and deformation data of the tested sample computed based on the raw data. "Pore_pressure_at_Mw 3.2.xlsx" is the numerically modeled pore pressure change at the hypocenter of the Mw 3.2 earthquake relative to the start of the first stimulation in the Pohang EGS.</p