Reservoir landslides represent a significant geological hazard that jeopardizes the safety of reservoirs. Deformation monitoring and numerical simulation are essential methodologies for elucidating the evolutionary patterns of landslides. Nonetheless, the existing approaches exhibit limitations in revealing the potential deformation mechanism. Consequently, this study proposes an innovative strategy that incorporates interferometric synthetic aperture radar (InSAR) deformation characteristics alongside fluid-solid coupling stress analysis to investigate the deformation, focusing on the Shuizhuyuan landslide within the Three Gorges Reservoir area as a case study. Using temporary coherence point InSAR technology, significant motion units were identified, with a maximum deformation rate of -60 mm/yr. The complete deformation time series reveals three independent components of landslide movement and their trigger factors geometrically. Subsequently, the saturation permeability coefficient of the sliding mass in the seepage analysis is modified with the assistance of InSAR deformation. Then, we coupled the seepage analysis results to FLAC3D model for stress and strain analysis, and determined the seepage-induced progressive failure mechanism and the deformation mode of the Shuizhuyuan landslide, driven by reservoir water-level (RWL) drop. The numerical simulation results aid in interpreting the deformation mechanism of different spatial and temporal patterns of landslides from three aspects: hydrodynamic pressure from rainfall infiltration, groundwater hysteresis caused by RWL drop, and seepage forces from RWL rise. Furthermore, our findings reveal that the dynamic factor of safety (FOS) of landslide during the InSAR observation period is highly consistent with the periodic fluctuations of the RWL. However, there is also a small trend of overall decline in FOS that cannot be ignored.

Urban forest trees are vital components of urban ecosystems, offering a range of benefits that are essential for improving the livability and sustainability of cities, providing numerous advantages for both the environment and public health. They enhance air quality by filtering pollutants, assist in regulating urban temperatures, and alleviate the urban heat island effect, which can result in substantial energy savings. Trees are often vulnerable to pathogens and pests that can cause significant damage. A survey of different trees in five provinces of Iran revealed a severe decline and dieback disease on woody plants. The affected trees included ailanthus, cedrus, cypress, ash, haloxylon, walnut, magnolia, black mulberry, paulownia, pine, oriental plane, apricot, wild pear, and elm trees. Samples of symptomatic branches and trunks were collected, and the causal fungal pathogen was isolated on potato dextrose agar (PDA) media. A total of 90 fungal isolates were obtained from trees (60 isolates) and insects (30 isolates) and then morphological investigations were done for all isolates. Molecular identification was confirmed through sequencing of the ITS and tub2 regions. This study reports 14 new hosts for Paecilomyces formosus in Iran and worldwide. Pathogenicity tests were conducted on detached branches of apricot, ailanthus, cypress, pine, sycamore, and walnut trees. The study showed that most isolates were pathogenic to six woody plants, and some isolates were associated with disease for eight woody plant species. Additionally, potential vectors and reservoirs for P. formosus were assessed in different beetles, including Aeolesthes sarta, Scolytus kirschii, and Orthotomicus erusus in Tehran, Alborz, Qazvin, Lorestan, and Zanjan Provinces. The results confirmed the potential of beetles for the transmission and maintenance of P. formosus.

The benefits of using cryogenic liquid nitrogen shock to enhance coal permeability have been confirmed from experimental perspectives. In this paper, we develop a fully coupled thermo-elastic model in combination with the strain-based isotropic damage theory to uncover the cooling-dominated cracking behaviors through three typical cases, i.e. coal reservoirs containing a wellbore, a primary fracture, and a natural fracture network, respectively. The progressive cracking processes, from thermal fracture initiation, propagation or cessation, deflection, bifurcation to multi-fracture interactions, can be well captured by the numerical model. It is observed that two hierarchical levels of thermal fractures are formed, in which the number of shorter thermal fractures consistently exceeds that of the longer ones. The effects of coal properties related to thermal stress levels and thermal diffusivity on the fracture morphology are quantified by the fracture fractal dimension and the statistical fracture number. The induced fracture morphology is most sensitive to changes in the elastic modulus and thermal expansion coefficient, both of which dominate the complexity of the fracture networks. Coal reservoir candidates with preferred thermal-mechanical properties are also recommended for improving the stimulation effect. Further findings are that there exists a critical injection temperature and a critical in-situ stress difference, above which no thermal fractures would be formed. Preexisting natural fractures with higher density and preferred orientations are also essential for the formation of complex fracture networks. The obtained results can provide some theoretical support for cryogenic fracturing design in coal reservoirs. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Reservoir fracturing stimulation is the key to constructing an enhanced geothermal system (EGS) for geothermal development in hot dry rock (HDR) reservoir. To clarify the crack propagation law of HDR fracturing, a 3D thermo-hydro-mechanical coupling simulation model of fracture propagation is produced based on the continuum-discontinuum element method (CDEM-THM3D). The correctness of the CDEM-THM3D model is validated by the theoretical solution of the nonisothermal soil consolidation model and Penny fracture model. Then, hydraulic fracturing numerical simulations are performed to analyse the influence of controlling variables on fracture propagation. The results indicate that the thermal tensile stress induced by injecting cold water can decrease reservoir fracture pressure and fracture extension pressure, causing an increasement in fracture width and a reduction in fracture length. Increasing thermal expansion coefficient and temperature difference enhances the effect of thermal stresses and even creates new branch fractures. A large elastic modulus favours an increase in fracture length, while large rock tensile strength and minimum horizontal stress lead to a decrease in fracture length. With increasing injection flow rate and fracturing fluid viscosity, the reservoir fracture pressure and the fracture width rise significantly, and the fracture easily breaks through the barrier of the high-stress compartment.