Hiking trails are a basic type of tourist infrastructure, which, on the one hand, make areas available for tourist traffic, and on the other hand, can contribute to the protection of the natural environment(if they are well designed and maintained). Owing to the variety of performed functions, their designation is determined by several factors: natural, technical, economic, social. Networks of trails change constantly. The aim of this article is to determine exactly what factors influence transformations within the hiking trail networks and what is their significance. To this end, three study areas in the Sudetes were analysed: one on the Polish side of the Sudetes – the Table(Sto?owe) Mountains, and two on the Czech side – the rock town near the village of Sloup v ?echách and the central part of Zlatohorská vrchovina. An analysis of changes in the shape of the networks over time was carried out, as well as surveys of institutions that were responsible for or influenced these transformations. These areas are characterised by a significant level of changes in the trail network. Among the factors influencing these changes, the tourist attractiveness of the area, the resilience of the environment, the intensity of tourism traffic, the environmental transformations associated with it, the history of tourism development and land ownership changes should be considered the most important. At each stage of forming networks, the key factor should be tourists' needs, including the desire to escape the urbanised environment. For this reason, trails should avoid roads with artificial(hard) surfaces and heavy automobile traffic.

With the rapid urbanization process, the space of traditional villages in China is undergoing significant changes. Studying the spatial evolution of traditional villages is significant in promoting rural spatial transformation and realizing rural revitalization and sustainable rural development. Based on the traceability analysis of spatial production theory, this paper constructed an analytical framework for the spatial production evolution of traditional villages, analyzed the spatial evolution process and characteristics of traditional villages by using buffer analysis, spatial syntax, and other research methods, and revealed the characteristics of the spatial production evolution of traditional villages and the driving mechanism. The results show that:(1) The village spatial formation and development follow the village life cycle theory and usually develop from embryonic villages to diversified and integrated villages;(2) The evolution of village spatial production is characterized by the diversity of material space, the sublimation of daily life space, and the integration of social system space and generalization of emotional space;(3) The evolution of village spatial production from backward and poor village to ecologically well-off village is influenced by a combination of factors;(4) The village has formed a spatial structure of "peopleland-scape-culture-industry", realized comprehensive reconstruction and spatial reproduction. The study results reflect the spatial evolution characteristics of traditional villages in mountainous areas in a more comprehensive way, which helps to promote the protection and development of traditional villages in mountainous areas and, to a certain extent, provides a reference for the development of rural revitalization.

The sustainability of environmental management initiatives, such as watershed management programs, relies on the presence of effective institutions at the watershed level. However, there needs to be more empirical evidence from evaluating the effectiveness of watershed-level institutions. Therefore, this study presents a pioneering effort to evaluate the effectiveness of Nepal's first watershed conservation committee at the watershed scale, focusing on the case of the Khageri Khola watershed in Central Nepal. The study involved conducting a household survey, key informant interviews, focus group discussions, and field observations to collect and analyze the data. Descriptive analysis, index value calculation, and chisquare statistics were then employed to summarize the results regarding local respondents' perceptions of twelve institutional characteristics, their rationalities, and their association with socio-demographic variables. The results reveal that the watershed conservation committee was perceived as performing well in managing the watershed. Specifically, good interaction, appropriate scale, technical, environmental, social, organizational, and government rationality were perceived as highly effective, with an average index value of less than 0.36. In contrast, clarity of objectives and economic rationality showed moderate effectiveness, with an average index value ranging from 0.36 to 0.65. However, the results suggested that adaptiveness, compliance capacity, and financial rationality merit increased attention, intending to improve their performance. Further, the results showed the association of socio-demographics with respondents' perceptions of various indicators of institutional characteristics and their rationalities. Therefore, the study provides valuable insights for policymakers, researchers, and development practitioners charged with designing sustainable and effective programs and institutions. To enhance the effectiveness and sustainability of watershed management programs, we recommend establishing a policy-guided institutional mechanism at the watershed scale. This mechanism should be based on various institutional characteristics and rationalities and should consider the extant variability in the sociodemographic and topographic characteristics of the watershed.

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken areas. However, spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation data. This research, leveraging night-time light remote sensing imagery and land cover data, conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquakeprone areas. It introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these regions. To validate the proposed methods, the 2008 Wenchuan earthquake-affected area in China was selected as a representative study area. The results indicated that the average Digital Number(DN) values in socio-economically impacted areas showed a trend of rising, falling, and then rising again after the earthquake. DN values in three types of damaged areas including Type Ⅱ,Type Ⅲ, and Type Ⅳ exceeded preearthquake levels. The analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake, whereas factors such as slope, elevation, lithology, and faults had a stronger influence on urban land expansion after the earthquake. It can be seen that, in view of the differences in the natural conditions of regions for post-disaster reconstruction, the local government need to actively adjust and adapt to urban spatial planning, so as to leverage the scale effect of large-scale inputs of funds, facilities, human resources and other factors after the disaster, thus enhancing resilience and recovery efficiency in response to disaster impacts.

The critical rainfall of runoff-initiated debris flows is utmost importance for local early hazard forecasting. This paper presents research on the critical rainfall of runoff-initiated debris flows through comparisons between slope gradients and three key factors, including topographic contributing area, dimensionless discharge, and Shields stress. The rainfall amount was estimated by utilizing in-situ rainfall records and a slope-dependent Shields stress model was created. The created model can predict critical Shields stress more accurately than the other two models. Furthermore, a new dimensionless discharge equation was proposed based on the corresponding discharge-gradient datasets. The new equation, along with factors such as contributing area above bed failure sites, channel width, and mean diameter of debris flow deposits, predicts a smaller rainfall amount than the in-situ measured records. Although the slope-dependent Shields stress model performs well and the estimated rainfall amount is lower than the in-situ records, the sediment initiation in the experiments falls within sheet flow regime due to a large Shields stress. Therefore, further sediment initiation experiments at a steeper slope range are expected in the future to ensure that the sediment transport belongs to mass failure regime characterized by a low level of Shields stress. Finally, a more accurate hazard forecast on the runoff-initiated debris flow holds promise when the corresponding critical slopedependent dimensionless discharge of no motion, fluvial sediment transport, mass flow regime, and sheet flow regime are considered.

Rock fragmentation plays a critical role in rock avalanches, yet conventional approaches such as classical granular flow models or the bonded particle model have limitations in accurately characterizing the progressive disintegration and kinematics of multideformable rock blocks during rockslides. The present study proposes a discrete-continuous numerical model, based on a cohesive zone model, to explicitly incorporate the progressive fragmentation and intricate interparticle interactions inherent in rockslides. Breakable rock granular assemblies are released along an inclined plane and flow onto a horizontal plane. The numerical scenarios are established to incorporate variations in slope angle, initial height, friction coefficient, and particle number. The evolutions of fragmentation, kinematic, runout and depositional characteristics are quantitatively analyzed and compared with experimental and field data. A positive linear relationship between the equivalent friction coefficient and the apparent friction coefficient is identified. In general, the granular mass predominantly exhibits characteristics of a dense granular flow, with the Savage number exhibiting a decreasing trend as the volume of mass increases. The process of particle breakage gradually occurs in a bottom-up manner, leading to a significant increase in the angular velocities of the rock blocks with increasing depth. The simulation results reproduce the field observations of inverse grading and source stratigraphy preservation in the deposit. We propose a disintegration index that incorporates factors such as drop height, rock mass volume, and rock strength. Our findings demonstrate a consistent linear relationship between this index and the fragmentation degree in all tested scenarios.

High-resolution landslide images arerequired for detailed geomorphological analysis incomplex topographic environment with steep andvertical landslide distribution. This study proposed avertical route planning method for unmanned aerialvehicles(UAVs), which could achieve rapid imagecollection based on strictly calculated routeparameters. The effectiveness of this method wasverified using a DJI Mavic 2 Pro, obtaining highresolution landslide images within the Dongchuan debris flow gully, in the Xiaojiang River Basin, Dongchuan District, Yunnan, China. A threedimensional(3D) model was constructed by the structure-from-motion and multi-view stereo(Sf MMVS). Micro-geomorphic features were analyzed through visual interpretation, geographic information system(GIS), spatial analysis, and mathematical statistics methods. The results demonstrated that the proposed method could obtain comprehensive vertical information on landslides while improving measurement accuracy. The 3D model was constructed using the vertically oriented flight route to achieve centimeter-level accuracy(horizontal accuracy better than 6 cm, elevation accuracy better than 3 cm, and relative accuracy better than 3.5 cm). The UAV technology could further help understand the micro internal spatial and structural characteristics of landslides, facilitating intuitive acquisition of surface details. The slope of landslide clusters ranged from 36° to 72°, with the majority of the slope facing east and southeast. Upper elevation levels were relatively consistent while middle to lower elevation levels gradually decreased from left to right with significant variations in lower elevation levels. During the rainy season, surface runoff was abundant, and steep topography exacerbated changes in surface features. This route method is suitable for unmanned aerial vehicle(UAV) landslide surveys in complex mountainous environments. The geomorphological analysis methods used will provide references for identifying and describing topographic features.

Rock avalanches are generally difficult to prevent and control due to their high velocities and the extensive destruction they cause. However, barrier structures constructed along the path of a rock avalanche can partially mitigate the magnitudes and consequences of such catastrophic events. We selected a rock avalanche in Nayong County, Guizhou Province, China as a case to study the effect of the location and height of a retaining wall on the dynamic characteristics of rock avalanche by using both actual terrain-based laboratory-model tests and coupled PFC~(3D)–FLAC~(3D) numerical simulations. Our findings demonstrate that a retaining wall can largely block a rock avalanche and its protective efficacy is significantly influenced by the integrity of the retaining wall. Coupled numerical simulation can serve as a powerful tool for analyzing the interaction between a rock avalanche and a retaining wall, facilitating precise observations of its deformation and destruction. The impact-curve characteristics of the retaining wall depend upon whether or not the rock avalancheinduced destruction is taken into account. The location of the retaining wall exerts a greater influence on the outcome compared to the height and materials of the retaining wall, while implementing a stepped retaining-wall pattern in accordance with the terrain demonstrates optimal efficacy in controlling rock avalanche.

Machine learning(ML)-based prediction models for mapping hazard(e.g., landslide and debris flow) susceptibility have been widely developed in recent research. However, in some specific areas, ML models have limited application because of the uncertainties in identifying negative samples. The Parlung Tsangpo Basin exemplifies a region prone to recurrent glacial debris flows(GDFs) and is characterized by a prominent landform featuring deep gullies. Considering the limitations of the ML model, we developed and compared two combined statistical models(FA-WE and FA-IC) based on factor analysis(FA), weight of evidence(WE), and the information content(IC) method. The final GDF susceptibility maps were generated by selecting 8 most important static factors and considering the influence of precipitation. The results show that the FA-IC model has the best performance. The areas with a very high susceptibility to GDFs are primarily located in the narrow valley section upstream, on both sides of the valley in the middle and downstream of the Parlung Tsangpo River, and in the narrow valley section of each tributary. These areas encompass 86 gullies and are characterized as "narrow and steep".

Volcanic lakes in the Kuril-Kamchatka region are difficult to access, and for this reason, they remain poorly studied, with only scattered and brief data available. The authors have conducted a study of 10 lake basins using modern digital echolocation survey techniques and have also compiled and summarized published data for 15 lakes in the region, calculating their main morphometric characteristics. It has been established that many caldera lake basins are modified by young explosive funnels, extrusive or effusive domes, and exhibit traces of hydrothermal activity. While lakes of the same genetic type in the Kuril-Kamchatka region are similar in depth and depression forms, the group of caldera lakes shows less homogeneity across all morphometric indicators. It was found that the absolute heights of the reservoirs on Kamchatka Peninsula are generally greater than those on the Kuril Islands, as is often the case with the size of their basins. The volcanic lakes under study can rapidly change their volume and shape under the influence of endogenous processes. For the first time for this region, on the base of repeated observations, underwater extrusive dome rate growth and the approximate rates of 2 lake level changes were calculated. Repeated observations of lakes in the Ksudach calderas(Kamchatka) and on Simushir Island indicate approximate rates of level changes: a decrease ranging within 0.5-0.6 m per year(over a 27-year observation interval) and an increase reaching up to 0.26 m per year(over a 48-year interval). The growth rate of the underwater extrusive dome in Lake Shtyubel has averaged 1-1.6 m per year over the past 25 years. This analysis has facilitated the first generalization regarding the morphology and developmental features of crater and caldera lakes in the Kuril-Kamchatka region of Russia, representing an important step in their study. The results obtained will provide a solid foundation for subsequent research in this region and may be of interest to researchers studying other volcanic lakes.

Environmental conditions can change markedly over geographical distances along elevation gradients, making them natural laboratories to study the processes that structure communities. This work aimed to assess the influences of elevation on Tropical Montane Cloud Forest plant communities in the Brazilian Atlantic Forest, a historically neglected ecoregion. We evaluated the phylogenetic structure,forest structure(tree basal area and tree density) and species richness along an elevation gradient, as well as the evolutionary fingerprints of elevation-success on phylogenetic lineages from the tree communities. To do so, we assessed nine communities along an elevation gradient from 1210 to 2310 m a.s.l. without large elevation gaps. The relationships between elevation and phylogenetic structure, forest structure and species richness were investigated through Linear Models. The occurrence of evolutionary fingerprint on phylogenetic lineages was investigated by quantifying the extent of phylogenetic signal of elevation-success using a genus-level molecular phylogeny. Our results showed decreased species richness at higher elevations and independence between forest structure, phylogenetic structure and elevation. We also verified that there is a phylogenetic signal associated with elevation-success by lineages. We concluded that the elevation is associated with species richness and the occurrence of phylogenetic lineages in the tree communities evaluated in Mantiqueira Range. On the other hand, elevation is not associated with forest structure or phylogenetic structure. Furthermore, closely related taxa tend to have their higher ecological success in similar elevations. Finally, we highlight the fragility of the tropical montane cloud forests in the Mantiqueira Range in face of environmental changes(i.e. global warming) due to the occurrence of exclusive phylogenetic lineages evolutionarily adapted to environmental conditions(i.e. minimum temperature) associated with each elevation range.

The increasing demand for water and energy resources has led to widespread dam construction, particularly in ecologically sensitive regions like the Himalayan Range. This study focuses on the Uttarakhand state in the Western Himalayas, where hydroelectric projects(HEPs) have significantly altered river flow regimes. The research investigates the impact of flow alterations on the composition and structure of riparian vegetation in the Garhwal Himalayas, specifically analysing four rivers regulated by hydroelectric projects. Utilizing the paired-reach comparison method, control(undisturbed), diverted(downstream of barrage/dam), and altered flow conditions(downstream of water outlet) were examined. The research reveals diverse and unique riparian ecosystems, with 89 genera and 113 taxa identified, showcasing the dominance of families like Asteraceae and Lamiaceae. The study unveils the structural importance of key species such as Berberis asiatica and Artemisia nilagirica. The density, diversity, and richness of shrub and herb species vary significantly across flow conditions. Notably, altered flow conditions demonstrate resilience in vegetation structure, while diverted conditions exhibit decreased species richness and density. The study emphasizes the importance of nuanced environmental flow management for mitigating adverse effects on riparian biodiversity in the fragile Himalayan region. These findings contribute to the global discourse on dam impacts and riparian ecology, shedding light on the complexities of this dynamic relationship in a vulnerable ecosystem.

Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers. The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya) for the years 1993, 2000, 2010, and 2019 using Landsat Thematic Mapper(TM), Enhanced Thematic Mapper(ETM), and Operational Land Imager(OLI) datasets. A total of 251 glaciers, each having an area above 0.5 km~2, were identified, which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods: 1993-2000, 2000-2010, and 2010-2019. The total glacierized area was 996 ± 62 km~2 in 1993, which decreased to 973 ± 70 km~2 in 2019. The mean rate of glacier area loss was higher in the recent decade(2010-2019), at 0.036 km~2, compared to previous decades(0.029 km~2 in 2000-2010 and 0.025 km~2 in 1993-2000). Supraglacial debris cover changes are also mapped over the period of 1993 and 2019. It is found that the supraglacial debris cover increased by 14.12 ± 2.54 km~2(15.2%) during 1993-2019. Extensive field surveys on Chhota Shigri, Panchi II, Patsio, Hamtah, Mulkila, and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets. Controls of various morphological parameters on retreat were also analyzed. It is observed that small, clean ice, south oriented glaciers, and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin.

During the construction of cast-in-place piles in warm permafrost, the heat carried by concrete and the cement hydration reaction can cause strong thermal disturbance to the surrounding permafrost. Since the bearing capacity of the pile is quite small before the full freeze-back, the quick refreezing of the native soils surrounding the cast-in-place pile has become the focus of the infrastructure construction in permafrost. To solve this problem, this paper innovatively puts forward the application of the artificial ground freezing(AGF) method at the end of the curing period of cast-in-place piles in permafrost. A field test on the AGF was conducted at the Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment(34°51.2' N, 92°56.4' E) in the Qinghai Tibet Plateau(QTP), and then a 3-D numerical model was established to investigate the thermal performance of piles using AGF under different engineering conditions. Additionally, the long-term thermal performance of piles after the completion of AGF under different conditions was estimated. Field experiment results demonstrate that AGF is an effective method to reduce the refreezing time of the soil surrounding the piles constructed in permafrost terrain, with the ability to reduce the pilesoil interface temperatures to below the natural ground temperature within 3 days. Numerical results further prove that AGF still has a good cooling effect even under unfavorable engineering conditions such as high pouring temperature, large pile diameter, and large pile length. Consequently, the application of this method is meaningful to save the subsequent latency time and solve the problem of thermal disturbance in pile construction in permafrost. The research results are highly relevant for the spread of AGF technology and the rapid building of pile foundations in permafrost.

Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly. Present research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest, central Nepal. Data were collected from 300 sample plots within vertical elevation bands of 10, ranging from 1365 to 2450 m asl. A random sampling method was used for data collection in three seasons, winter, premonsoon and post monsoon seasons. Diameter at breast height(DBH) was used to broadly categorize the plant individual into trees, saplings and seedlings. The tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per hectare. Species richness of tree and sapling showed statistically significant unimodal pattern, which peaked at midelevation. Elevation showed a strong and positive linear correlation with the seedling density(Deviance = 0.99, p < 0.001) and a significant hump-shaped relationship with sapling density(Deviance = 0.95, p < 0.001). Similarly, elevations showed a statistically significant negative hump-shaped relationship with all trees, saplings and seedling stages(Deviances = 0.89, 0.87 and 0.57). The highest values of the ShannonWiener index and the lowest value of the Simpson index were found at mid-elevation for all growth forms. Nearly 92% of tree species were found at regenerating stage; 49% in a good renewal regeneration status, 32% in fair renewal regeneration, and 11% at a poor regenerating condition. Nevertheless, 4% of tree species were reported as non-regenerating stages and 4% were newly introduced species. Hence, the regeneration status of the study area was considered fairly well since sapling(78.5%) > seedling(10.6%) ≤ mature(10.9%). Among tested environmental variables, elevation and annual mean rainfall were the most influential factors in the regeneration of tree species.

The implementation of Ecological Function Protection Zone(EFPZ) policy is significant for the ecological restoration and conservation of soil and water in the territory space. This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function, based on land use data from 2005, 2008, 2010, 2015 and 2020, by conducting a counterfactual simulation along with the Geo SOSFLUS model and the In VEST model. The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1) From 2010 to 2020, as the EFPZ was implemented, the water conservation in the study area was increasing year by year, with a growth rate of 0.03 × 10~8 m~3·a~(-1). On the other hand, the simulated water conservation capacity without the implementation of EFPZ decreased year by year, with a decrease rate of 0.01 × 10~8 m~3·a~(-1).(2) The EFPZ accounts for only 23% of the total area, but the contribution rate of water conservation reaches 80%. The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally, while the counterfactual simulation values exhibit a decreasing trend.(3) The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ. The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ.

In the restoration of degraded wetlands, fertilization can improve the vegetation-soilmicroorganisms complex, thereby affecting the organic carbon content. However, it is currently unclear whether these effects are sustainable. This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics, soil physicochemical properties, and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen, phosphorus, and organic mixed fertilizer. The following results were obtained: The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands. Three months after fertilization, nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands, whereas after 15 months, organic compost enhanced the soil organic carbon level in severely degraded wetlands. Structural equation modeling indicates that fertilization decreases the soil p H and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation. Three months after fertilization, nitrogen fertilizer showed a direct positive effect on soil organic carbon. However, organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture. After 15 months, none of the fertilizers significantly affected the soil organic carbon level. In summary, it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.

Land dissection density(LDD) provides morphological evidence regarding prior intense soil erosion and quantifies the distribution of land dissections. A comprehensive understanding of the potential factors influencing the spatial pattern and value of the LDD is vital in geological disasters, soil erosion, and other related domains. Land dissection phenomena in China affects large areas with different morphological, pedological, and climatic characteristics. Prior studies have focused on the potential factors influencing the LDD at a watershed scale. However, these results are insufficient to reflect the status quo of dissection development and its primary influencing factors on a national scale. LDD's spatial patterns and the dominant factors at a regional scale in millions of square kilometers remain to be ascertained. This study used the geomorphon-based method and the geographical detector model to quantify the spatial pattern of LDD over China and identify the dominant factors affecting this pattern in China's six first-order geomorphological regions(GR1～GR6). The results yield the following findings:(1) LDD in China ranges from 0～4.55 km/km~2, which is larger in central and eastern regions than in other regions of China;(2) dominant factors and their dominant risk subcategories vary with each geomorphological region's primary internal and external forces;(3) the influence of natural factors is more significant on the large regional scale in millions of square kilometers compared to anthropogenic factors; relief degree of land surface(RDLS) is dominant in GR1, GR2, and GR5; the slope is dominant in GR6, soil type is dominant in GR3 and GR4, and lithology plays a critical role in the dominant interactions of GR3, GR4, and GR6;(4) the interactions between factors on LDD's spatial pattern have a more significant effect than individual factors.

In northeastern Sicily(Italy), sandstone rock masses widely crop out as cover deposits over crystalline terrains belonging to the orogenic belt. Despite being part of the same geological formation, these sandstones are characterized by highly different features in terms of texture and physico-mechanical properties. This poses a scientific question on the possibility of tracing these rocks to a single statistical model, which could be representative of their main engineering geological properties. Therefore, it is worth investigating on the possible reasons of such differences, that should be searched either in the current geographical sandstone distribution or in the rock texture. For this study, sandstone samples were collected from different sites and were analyzed at both the hand and thin section scales. Three sandstone types were recognized, characterized by a different texture. Then, the laboratory characterization allowed estimating their main physico-mechanical and ultrasonic properties, such as porosity, density, mechanical strength, deformability, and ultrasonic velocities. The rock mechanical strength proved linked to the rock compactness and to the presence of lithic fragments, while pores and a pseudo-matrix between grains represent weakening features. Rock data were also statistically analyzed by grouping the specimens according to a geographical criterion, with respect to their sampling area, but no link was found between location and rock properties. Finally, with the aim of achieving mathematical laws that could be used to predict some rock properties from others, useful for practical purposes when dealing with such a high property variability, single and multiple regression analyses were carried out. Results show that the Uniaxial Compressive Strength, porosity, and P-wave velocity are the best predictors for a quick, indirect estimation of the main physico-mechanical parameters. The methodological approach developed for this research can be taken as reference to study other worldwide cases, involving rocks characterized by a wide range of physico-mechanical properties and covering large regional territories.

The control of large deformation problems in layered soft rock tunnels needs to solve urgently. The roof problem is particularly severe among the deformation issues in tunnels. This study first analyzes the asymmetric deformation modes in layered soft rock tunnels with large deformations. Subsequently, we construct a mechanical model under ideal conditions for controlling the roof of layered soft rock tunnels through high preload with the support of NPR anchor cables. The prominent roles of long and short NPR anchor cables in the support system are also analyzed. The results indicate the significance of high preload in controlling the roof of layered soft rock tunnels. The short NPR anchor cables effectively improve the integrity of the stratified soft rock layers, while the long NPR anchor cables effectively mobilize the self-bearing capacity of deep-stable rock layers. Finally, the high-preload support method with NPR anchor cables is validated to have a good effect on controlling large deformations in layered soft rock tunnels through field monitoring data.

Understanding the unstable evolution of railway slopes is the premise for preventing slope failure and ensuring the safe operation of trains. However, as two major factors affecting the stability of railway slopes, few scholars have explored the unstable evolution of railway slopes under the joint action of rainfall-vibration. Based on the model test of sandy soil slope, the unstable evolution process of slope under locomotive vibration, rainfall, and rainfall-vibration joint action conditions was simulated in this paper. By comparing and analyzing the variation trends of soil pressure and water content of slope under these conditions, the change laws of pore pressure under the influence of vibration and rainfall were explored. The main control factors affecting the stability of slope structure under the joint action conditions were further defined. Combined with the slope failure phenomena under these three conditions, the causes of slope instability resulting from each leading factor were clarified. Finally, according to the above conclusions, the unstable evolution of the slope under the rainfallvibration joint action was determined. The test results show that the unstable evolution process of sandy soil slope, under the rainfall-vibration joint action, can be divided into: rainfall erosion cracking, vibration promotion penetrating, and slope instability sliding three stages. In the process of slope unstable evolution, rainfall and vibration play the roles of inducing and promoting slide respectively. In addition, the deep cracks, which are the premise for the formation of the sliding surface, and the violent irregular fluctuation of soil pressure, which reflects the near penetration of the sliding surface, constitute the instability characteristics of the railway slope together. This paper reveals the unstable evolution of sandy soil slopes under the joint action of rainfallvibration, hoping to provide the theoretical basis for the early warning and prevention technology of railway slopes.

The compaction characteristics of gravelly soil are affected by gravel hardness. To investigate the evolution and influencing mechanism of different gravel hardness on the compaction characteristics of gravelly soil, heavy compaction tests and crushing tests were conducted on gravelly soils with gravels originated from hard, soft and extremely soft rocks. According to orthogonal experiments and variance analysis, it was found that hardness has a significant impact on the maximum dry density of gravelly soil, followed by gravel content, and lastly, moisture content. For gravel compositions with an average saturated uniaxial compressive strength less than 60 MPa, the order of compacted maximum dry density is soft gravels > hard gravels > extremely soft gravels. Each type of gravelly soil has a threshold for gravel content, with 60% for hard and soft gravels and 50% for extremely soft gravels. Beyond these thresholds, the compacted dry density decreases significantly. There is a certain interaction between hardness, gravel content, and moisture content. Higher hardness increases the influence of gravel content, whereas lower hardness increases the influence of moisture content. Gravelly soils with the coarse aggregate(CA) between 0.7 and 0.8 typically achieve higher dry densities after compaction. In addition, the prediction equations for the particle breakage rate and CA ratio in the Bailey method were proposed to estimate the compaction performance of gravelly soil preliminarily. The results further revealed the compaction mechanism of different gravelly soils and can provide reference for subgrade filling construction.