Zhe Jiang Institute of Geology and Mineral Resource

It is crucial to accurately measure the volume change of specimens in triaxial tests on unsaturated soils. A new type of inner chamber structure has been designed for measuring volume changes, which can accurately measure the volume change of unsaturated soils during monotonic loading tests. Compared to conventional double chamber triaxial systems, the new inner chamber structure has higher precision and compatibility, and the inner chamber can be assembled under air-free water. The inner chamber assembled underwater avoids the problem that the air bubbles being trapped in the inner chamber, significantly reducing the impact of residual air in the system. A solid specimen made of stainless steel was used to calibrate the newly designed inner chamber. Under the net confining pressure (the difference between cell pressure and the initial cell pressure) of 400 kPa, the volume change error of system is only 0.037% of specimen volume, the measurement error is very small. The contact surface between the loading ram and the top cover is coated with Teflon material and smeared with Vaseline to reduce friction, and the friction force measured by high-precision force gauge is 4.14 N. Drained shear test was conducted on an undisturbed saturated soft clay specimen, where the volume change in the saturated soil specimen during drainage was used to verify the accuracy and precision of the inner chamber volume measurement method. The volume change error measured by the system during consolidation and shearing are 0.102% and 0.067% of specimen volume, respectively. The results indicate that the newly designed inner chamber structure is feasible for volume change measurement and has high precision.

Abstract As one of the major geological disasters in southeastern China, typhoon-induced vegetation slope instability causes significant loss of life and property each year. This research quantitatively investigated the effects of wind and vegetation on slope dynamic field and soil strength through numerical simulation and soil strength degradation tests. Finally, we proposed an optimization method for stability assessment of vegetated slopes in the southeast coastal area. The results show that: 1) From 1999 to 2022, 86.1% of landslides occurred during typhoons with high wind speeds and precipitation. 2) The influence of wind on the dynamic response of vegetated slopes varies obviously with wind speeds. When the wind grade ≥ 13 (typhoon: 37.0 ~ 41.4m/s), vegetation canopy shaking significantly increases slope displacement. 3) When the wind speed is higher than that in working condition 4 (grade 10–11: 24.5 ~ 32.6m/s), the wind load promotes the degradation of soil strength, with the degradation parameter (Kτ) drastically decreasing by nearly 22.2%. 4) Compared with the traditional model, the optimized evaluation model is more sensitive. The calculated anti-sliding force increases by 10.62%~11.64%. The research results can improve the accuracy of slope stability assessment and provide a reasonable reference for the factor selection of typhoon-induced landslide risk assessment.

With the blooming of NFT platforms such as Opensea, metaverse has become the most booming concept in both industry and academia all around the universe. Compre-hending the way metaverse economy operates and the intrinsic value propping it has become the key to the essence of metaverse. We try to reveal the value basis of metaverse via two academic resources, media theory and attention economics, to describe the principle of value creation in metaverse economy. To better examine how the value of NFT projects is affected by human time and attention devoted to metaverse, we study a system with structured rules, e.g. blockchain games, to measure the players' time spent and quantify the players' rewards. A representative project, Aavegotchi is examined as a case. We analyse the data of Aavegotchi pixel ghosts such as price, rarity and player's time devoted. We find various interesting results which demonstrate how the value of NFTs is affected by various factors, and acquire some meaningful conclusions on the value of time in metaverse.

The analysis of the sediment 14C dating, grain sizes, sporopollen and micropaleontology in the BZK01 borehole in the Yangtze River Delta Plain was carried out. The sporopollen assemblages, the sedimentary environment evolution, the sedimentary facies and the paleoclimate characteristics revealed by the borehole since the Pliocene were discussed in combination with the gamma logging and the lithologic stratigraphy, and the quaternary multiple stratigraphic division of the borehole was established. The results show that the study area has undergone many environmental changes since Pliocene due to the influence of the primitive topography, the sea level changes, the land-sea changes, the paleoclimate changes and the Neotectonic movement. From bottom to top, the drilling holes reveal that the lithology and the strata are bedrock Changhe Formation, the Neogene-Quaternary sedimentary Jiaxing Formation, the Qiangang Formation, the Dongpu Formation, the Ningbo Formation and the Zhenhai Formation in turn. The sporopollen assemblage can be divided into 16 sporopollen belts. According to the periodic variation of the paleoclimate cycle during the warm, the humid and the cold and the dry periods, BZK01 drilling reflects that in the total area there are seven paleoclimatic cycles. The multi-stratigraphic division and correlation of the boreholes revealed that 151.9–278.0 m is the Pliocene-Early Pleistocene period of the alternating fluvial and lacustrine deposits, and there are two climatic cycles; 83.5–151.9 m is the Middle Pleistocene of the fluvial-lacustrine-shallow lacustrine depositional environment, which includes two climatic cycles. 15.4–83.5 m is the Late Pleistocene and sinks. From bottom to top, the sedimentary environment is the estuarine-fluvial-tidal-flat-littoral-fluvial facies, corresponding to Wangdian-Hangzhou transgression period, including two climatic cycles. 0–15.4 m is Holocene of the estuarine-fluvial-lagoon facies sedimentary environment, corresponding to Fuyang transgression, including one climatic cycle.

Multiple sets of organic-rich shales developed in the Upper Paleozoic of the northwestern Guizhong Depression in South China. However, the exploration of these shales is presently at a relatively immature stage. The Upper Paleozoic shales in the northwestern Guizhong Depression, including the Middle Devonian Luofu shale, the Nabiao shale, and the Lower Carboniferous Yanguan shale, were investigated in this study. Mineral composition analysis, organic matter analysis (including total organic carbon (TOC) content, maceral of kerogen and the vitrinite reflection (Ro)), pore characteristic analysis (including porosity and permeability, pore type identification by SEM, and pore size distribution by nitrogen sorption), methane isothermal sorption test were conducted, and the distribution and thickness of the shales were determined, Then the characteristics of the two target shales were illustrated and compared. The results show that the Upper Paleozoic shales have favorable organic matter conditions (mainly moderate to high TOC content, type I and II1 kerogen and high to over maturity), good fracability potential (brittleness index (BI) > 40%), multiple pore types, stable distribution and effective thickness, and good methane sorption capacity. Therefore, the Upper Paleozoic shales in the northern Guizhong Depression have good shale gas potential and exploration prospects. Moreover, the average TOC content, average BI, thickness of the organic-rich shale (TOC > 2.0 wt%) and the shale gas resources of the Middle Devonian shales are better than those of the Lower Carboniferous shale. The Middle Devonian shales have better shale gas potential and exploration prospects than the Lower Carboniferous shales.