过刊目录

  • 2023年, 20卷, 第11期
    刊出日期:2024-06-19
      

  • 全选
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  • UZUN Ali, AYLAR Faruk, ZEYBEK Halil ?brahim, ALEMDA? Sel?uk
    2023, 20(11): 3121-3137.
    Tors are mound-like rock landforms,resistant to erosion, that may sometimes reach the size of several storeys of house by volume. They may develop in different climate regions and different rock types, led by granitic rocks. In this study, tors developed in granitic rocks around Yaylal? village linked to Kürtün county in Gümü?hane were investigated. The study area is located in the eastern part of the Giresun mountain range in northeastern Turkey, 2000-2300 m above sea level. The aim of the study is to determine the natural environmental characteristics in tor formation and to reveal the effect of bedrock on tor formation. During field studies, 18 tors were selected by noting location, size and structural features, and dimensions were measured. Thin sections were first made from the rock samples taken from the tors and then the mineralogical composition was investigated by modal analysis method. As a result of this analysis, it was determined that the bedrock forming the tors is granite. During the field observations, it was determined that the intersecting vertical joints supported the formation of castle-like tors, while the horizontal joints supported the formation of pita pileshaped tors. There are also pseudokarstic shapes resembling kamenitza and karst pavement. In conclusion, joint sets causing local resistance differences directed the formation of tors, while excess slope affected surface erosion and suitability of climate conditions-controlled weathering rate.
  • WANG Guan-fu, LIN Chuang, ZHU Long, FENG De-cheng, XIN Yang-yang, ZHANG Feng
    2023, 20(11): 3138-3153.
    Two-phase closed thermosyphons(TPCTs)are widely used in infrastructure constructions in permafrost regions. Due to different climatic conditions, the effectiveness of TPCT will also be different, especially in the extremely cold region of the Da Xing'anling Mountains. In this study, a series of three-dimensional finite element TPCT embankment models were established based on the ZhanglingMohe highway TPCT test section in Da Xing'anling Mountains, and the thermal characteristics and the cooling effect of the TPCTs were analyzed. The results indicated that the TPCTs installed in the northeastern high-latitude regions is effective in cooling and stabilizing the embankment. The working cycle of the TPCTs is nearly 7 months, and the cooling range of the TPCTs can reach 3 m in this region. However, due to the extremely low temperature, the TPCT generates a large radial gradient in the permafrost layer.Meanwhile, by changing the climate conditions, the same type of TPCT embankment located in the Da Xing'anling Mountains, the Xiao Xing'anling Mountains, and the Qinghai-Tibet Plateau permafrost regions were simulated. Based on the comparison of the climate differences between the Qinghai-Tibet Plateau and Northeast China, the differences in the effectiveness of TPCTs were studied. Finally, the limitations of using existing TPCTs in high-latitude permafrost regions of China were discussed and the potential improvements of the TPCT in cold regions were presented.
  • Suraj MAL, Kavya AGRAWAL, Seema RANI, Pyarimohan MAHARANA, Viswanathan Anantha Venkat RAMAN
    2023, 20(11): 3154-3172.
    Land surface temperature(LST) is a crucial parameter for understanding the Earth's surface energy balance, which provides insights into climate dynamics and local environmental conditions.Thus, the present study aims to evaluate the spatial and elevation-wise trends in the daytime, nighttime,and mean LST across the Indus River Basin(IRB)using MODIS 8-day product for the period between 2002 and 2022. The elevation, cloud cover, and land cover type data are used for explaining the emerging LST trends. The Theil slope estimator and MannKendall significance test were used for estimating the seasonal and annual LST trends. The findings show warming in mean daytime(0.020-0.024℃/yr)(except winter and post-monsoon), nighttime(0.013-0.049℃/yr), and mean(0.001-0.042℃/yr) LST in all the seasons(highest in monsoon). The annual mean nighttime LST(0.025℃/yr) is rising significantly faster than the mean daytime LST(0.0016℃/yr),showing the presence of a “nighttime warming effect”,which possibly increases human discomfort,particularly during the warm pre-monsoon and humid monsoon season. Elevation-dependent warming(EDW) is predominant in mean daytime LST in two elevation zones, namely(i) 0-3 km and(ii)above 4 km, in all seasons, except in post-monsoon.In contrast, EDW in mean nighttime LST is observed up to 3 km and above 6 km in the basin in all the seasons, excluding post-monsoon. The warming trend in LST may be attributed to rising atmospheric moisture, cloud cover, declining snow cover, and changes in land cover to non-vegetated land. However,further investigations will involve exploring the underlying factors contributing to the observed anomalies in nighttime LST, considering variables such as regional energy balance and atmospheric stability. This research contributes to an understanding of the thermal dynamics in the mountain basin, aiding in climate studies, land management, and the development of effective adaptation strategies in the IRB.
  • HE Fei-long, XU Qian, WANG Na, XUE Fei, WANG Hui
    2023, 20(11): 3173-3185.
    The wind environment of a site is one of the important factors affecting the observation performance of large aperture and high-performance radio telescopes. Exploring the relationship between the effects of different terrains on wind flow is important to optimize the wind environment of the site. The terrain of the Qitai radio telescope(QTT) site located in east Tianshan Mountains at an elevation of about 1800 m was used to study the wind flow in the adjacent zone of antenna based on numerical simulation. The area from 600m south to 600m north of the antenna is defined as the antenna adjacent zone, and three groups of boundaries with different terrains are set up upstream and downstream,respectively. Since the zone where the antenna is located is a slope terrain, in order to verify the influence of terrain on the wind flow and to clarify the relationship between the influence of boundary terrain on the wind flow, a control group of horizontal terrain is constructed. The simulation results show that the wind flow is mainly influenced by the terrain.The highest elevation of the upstream and downstream boundary terrains affects the basic wind speed. The upstream boundary terrain has a greater impact on wind flow than the downstream boundary terrain. In addition, the wind speed profile index obtained by numerical simulation is smaller than the actual index for the wind from south. Therefore, the wind speed at the upper level(about 100 m) obtained by inversion based on the measured wind speed at the bottom(about 10 m) is also smaller than the actual wind speed.
  • ZKAN Bar, DENGIZ Orhan, ALABOZ Pelin, KAYA Nursa Serda
    2023, 20(11): 3186-3202.
    Soil quality determination and estimation is an important issue not only for terrestrial ecosystems but also for sustainable management of soils. In this study, soil quality was determined by linear and nonlinear standard scoring function methods integrated with a neutrosophic fuzzy analytic hierarchy process in the micro catchment. In addition,soil quality values were estimated using a support vector machine(SVM) in machine learning algorithms. In order to generate spatial distribution maps of soil quality indice values, different interpolation methods were evaluated to detect the most suitable semivariogram model. While the soil quality index values obtained by the linear method were determined between 0.458-0.717, the soil quality index with the nonlinear method showed variability at the levels of 0.433-0.651. There was no statistical difference between the two methods, and they were determined to be similar. In the estimation of soil quality with SVM, the normalized root means square error(NRMSE) values obtained in the linear and nonlinear method estimation were determined as 0.057 and 0.047, respectively. The spherical model of simple kriging was determined as the interpolation method with the lowest RMSE value in the actual and predicted values of the linear method while, in the nonlinear method, the lowest error in the distribution maps was determined with exponential of the simple kriging.
  • ZHANG Shi-hang, CHEN Yu-sen, LU Yong-xing, GUO Hao, GUO Xing, ZHOU Xiao-bing, ZHANG Yuan-ming
    2023, 20(11): 3203-3214.
    This study was conducted to analyze the variation of soil multifunctionality(SMF) along elevation and the driving factors in the Altun Shan.Soil samples(0–10 cm) were collected from 15 sites(H01 to H15) at every 200 m elevation interval,covering a total range from 900 m to 3500 m above mean sea level. We investigated climate factors(mean annual temperature, MAT; mean annual precipitation,MAP), soil environment(soil water content, electrical conductance, and pH), vegetation factors, and elevation to determine which of them are the main driving factors of the spatial variability of SMF in the Altun Shan. We explored the best-fit model of SMF along the changes in elevation using a structural equation model, performed variance partitioning analysis(VPA) on SMF with the “varpart” function to explain the relative contribution of various environmental factors to SMF changes, and used a random forest model for relative importance analysis.The results showed that SMF in the Altun Shan significantly increased with elevation in a linear trend.The main driver of changes in SMF was found to be MAP. Although the rise in elevation did not have a significant direct effect on changes in SMF, it could indirectly affect SMF by significantly influencing MAP,p H, MAT, and normalized difference vegetation index(NDVI). When considering climate, soil environment,and vegetation factors together, they explained 76% of the variation in SMF. The largest contribution to the variation in SMF was attributed to the independent effect of climate(0.31) and its interactive effect with soil(0.30). The relative importance of MAP on SMF changes was found to be the greatest. It is indicated that changes in SMF are caused by the combined effect of multiple environmental conditions. These findings are essential for understanding the spatial variability and drivers of SMF in dryland mountain ecosystems, especially concerning the function of mountain ecosystems in the context of global climatic changes.
  • LU Xian-jian, LI Zhen-bao, YAN Hong-bo, LIANG Yue-ji
    2023, 20(11): 3215-3232.
    Droughts are recurrent in southwest China due to the fragility and sensitivity of the karst environment. These events have serious impacts on local agricultural output, ecological diversity, and social stability. Understanding spatiotemporal variations and driving factors of drought in this area is of extreme importance for effective mitigation measures. The karst areas situated in southwest China were spatially divided into seven sub-regions according to the topography and degree of karst development. Drought indices, including vegetation condition index(VCI), temperature condition index(TCI), vegetation health index(VHI), normalized vegetation water supply index(NVSWI), and temperature vegetation drought index(TVDI), were calculated from MODIS data during 2000 and 2018for each sub-region, and drought patterns were examined. The results show that droughts were found to be concentrated in sub-regions such as karst basin,karst plateau, karst gorge, and karst depression areas.Furthermore, there were more drought conditions in karst areas than in non-karst areas. In addition,improvements to drought situation in the study period are significant(p<0.05), and mitigation areas respectively account for 80.1%(NVSWI), 74.2%(VCI),74.2%(VHI), 30.1%(TCI) and 33.2%(TVDI) of the study area, while drought expands slightly(<3.4%) in areas undergoing urban construction. Pearson's correlation coefficients between drought indices and temperature are generally above 0.5 in all sub-regions.However, the correlation coefficients between drought indices and precipitation mostly fall within the range of 0.3-0.4, indicating a weaker correlation. Our explanation for the spatiotemporal patterns of drought is that karst phenomena are the natural basis of drought and agricultural production is one of important driving forces. Positive changes of drought conditions have benefited from efforts to control rocky desertification and restore ecosystems over the past years.
  • WEN Li-li, WANG Jin-yue, DENG Yu-song, DUAN Xiao-qian
    2023, 20(11): 3233-3249.
    The hilly area of red soil in the central subtropical region of China has a long history of severe soil erosion due to its abundance of water, heat,and intense agricultural and forestry activities. The Sandshale red soil area is hot and rainy, the local land utilization rate and replanting index are high, and the soil easily weathers and erodes, resulting in infertile and sandy soils, extensive soil erosion and large erosion, with far-reaching impacts. In this study, the stability of soil aggregates was studied by the wet sieving method and Le Bissonais(LB) method in six land use patterns in the Sandshale red soil area,including natural forest(NF), Pinus massoniana(PM), Eucalyptus urophylla × E. grandis(EU),orchard(OR), wasteland(WL) and arable land(AL).The transport damage characteristics of the soil aggregates under concentrated water flow were analyzed by using the soil aggregates to simulate the soil surface roughness in the field using a steel scouring flume with a variable slope. The results showed that:(1) the total soil porosity of the natural forest was the highest, with 56.51% in A layer, which was 4.99% higher than the B layer, and the organic matter content ranged from 10.69 to 29.94 g.kg-1 and was highest in NF and lowest in AL;(2) the maximum mean weight diameter(MWD) obtained by the wet sieving method was 4.81 mm for natural forest, and the MWD was the lowest in OR and AL at 2.45-2.77mm. The MWD measured by the LB method was also highest in NF and lowest in AL. The contents of Fed and Ald have a strong correlation with the stability parameters of soil aggregates;(3) the Wr/Wi results for the six land use patterns were NF>PM>EU>WL>OR>AL; the NF had the strongest soil aggregate stability, followed by WL, PM and EU, and AL and OR had the weakest; the stability of soil aggregates gradually weakened as the soil depth increased.Comprehensive analysis shows that forest land has high soil stability and obvious advantages in soil erosion resistance. Strengthening the construction of artificial forests can be an important means to reduce soil erosion in red soil hilly region.
  • YAN Wei-po, WANG Qing, GUO Ya-lin, HU Qi, YANG Min, AN Yi-da
    2023, 20(11): 3250-3265.
    As climate change intensifies, finding an ecological indicator to quickly and accurately reflect the impact on mountain ecosystems is necessary. The low treeline/timberline, highly sensitive to climate variability and changes significantly within 5–10years, provides a new way to study the response to regional climate variability. This study explored the distribution and vertical displacement patterns of the low treeline in the Upper Minjiang River of China,using SPOT remote sensing images in 1999 and 2013and long-term positional observations. Using the Geodetector model, the study investigated the dominant climatic factors influencing the low treeline displacement. The results showed that the low treeline was located at 1700–3200 m elevation on sunny slopes(southeast, south, southwest, and west slopes) with slopes over 25°. From 1999 to 2013, the low treeline moved downward by 6 m from 2561±264m to 2555±265 m, along with a warm–humid climate tendency. The downward displacement was greater on slopes over 25° and shady slopes(-20 m and-10 m,respectively) than on slopes ≤ 25° and sunny slopes.Additionally, the downward was greater in the warm and humid Zagunao River Basin(-15 m) compared to the arid valley center(-7 m) and the cold Heishui River Basin(-3 m). Meanwhile, the low treeline displacement correlated negatively with precipitation and relative humidity variations at the significance level of 0.05, with correlation coefficients of-0.572and-0.551, respectively. Variations in relative humidity and temperature significantly affected the spatial differentiation of low treeline displacement with influencing power of 0.246(p =0.036 < 0.05)and 0.183(p =0.032 < 0.05), respectively. Thus, the low treeline is a moisture-limited line, and its formation and variation are closely related to regional water–heat balance. The study clarifies the indicative value of the low treeline for climate variability in mountain areas and can provide references for ecological restoration in arid valleys.
  • WANG Fang, YANG Zhong, LIU Kai, LU Chang-long
    2023, 20(11): 3266-3282.
    The permafrost table is an important index for the design and construction of roads in cold regions, so it is necessary to find a convenient,accurate and fast judgment method to determine the permafrost table. In this study, a three-field coupled model was established based on the hydrothermal salt coupling within the permafrost and the similarity theory, and the changes of the permafrost table under different temperature, moisture and salt conditions were numerically simulated by considering the transient temperature change and the influence of the permafrost layer on the seasonally thawed layer. In addition, an accelerated permafrost table test method was designed based on the time-domain variation and hydrothermal salt coupling by the similarity theory,which rapidly simulated the permafrost table change under different temperatures, moisture, and salts in the natural environment. Comparing the simulation and test results with the measured values in the field,the errors are less than 3%, which verified the feasibility of the method for determining the permafrost table, and the simulated results are better than the test results. Results show that the results of determining the permafrost table with a single index have different degrees of deviation, and the permafrost table obtained by the temperature index is the most accurate in general, and it is more accurate to use the average value of the three indexes as the permafrost table compared with a single index.
  • GUO Long-ji, TAO Zhi-gang, HE Man-chao, LIU Jian-ning, COLI Massimo
    2023, 20(11): 3283-3294.
    In a large ancient landslide, approximately 240,000 m3 of sediments were reactivated, posing a grave threat to the safety of iron ore stopes. To trace the deformation and evolution history of reactivated Landslide, we conducted geological surveys and combined real-time monitoring equipment to analyze the landslide data since 1986 and the deformation status of the reactivated Landslide. A multi-factor comprehensive landslide monitoring method and an Newton force early warning system(NFEWS) were established, focusing on underground stress, surface deformation information and landslide stability.Furthermore, we developed a four-level early warning grading standard, employing surface cracks and changes in underground stress thresholds as early warning indicators. This standard adds expert assessment to avoid false alarms and realize real-time dynamics of mining landslides during excavation and transportation. Through the case study and analysis of Nanfen open-pit mine, the NFEWS system offers valuable insights and solution for early warning of landslides in analogous open-pit mines. Finally, the evaluation index system of landslide hazard susceptibility was established by selecting the Newton force influence factor. A landslide susceptibility zoning map is constructed using the information value model. The rationality and accuracy are assessed from three perspectives: frequency ratio,landslide hazard point density, and receiver operating characteristic(ROC) curve. The improved Newton force landslide early warning system provides a good reference for the analysis and monitoring of the creep landslide evolution process.
  • SUN Hong-yue, WANG Xu, YU Yang, SHU Jun-wei, WANG Tian-long, LUO Rui, CHU Zhao-wei
    2023, 20(11): 3295-3311.
    A new anchor-siphon drainage combined method used for slope stabilization is proposed in this paper. It includes an anchoring section and a siphon drainage section. The novelty of the anchor-siphon drainage combined method is the realization of the drainage and anchoring in the one inclined borehole.The engineering cost of drilling and the resulting disturbance to the slope is reduced. To validate the feasibility of the proposed method, a numerical method that combines the pore water pressure distribution after siphon drainage and the anchoring force of the anchoring section is used to evaluate the safety of the slope with the anchor-siphon drainage method. The proposed method was illustrated and validated with the Hongpu Village landslide, in Tonglu County, Zhejiang Province, in China.Compared with the common anchor bar with the same length in the anchoring section, the factor of safety(FOS) for Hongpu Village slope with anchorsiphon drainage is increased by 0.085. The calculation method of the optimal length ratio between the drainage section and the anchoring section and its influencing factors were studied. For the different design parameters, there is always an optimal length ratio of the drainage section.Compared with the siphon drainage and full-length anchor bar with the same borehole length, the anchor-siphon drainage combined method shows better landslide prevention ability. Moreover, when the optimized parameters with a bond strength of 560kPa, a borehole inclination of 35°, and no reduction in length are used, the calculated safety factor is 1.316,which is significantly higher than the FOS of 1.131 for the slope with siphon drainage.
  • ZHAO Lian-heng, XU Xin, LYU Guo-shun, HUANG Dong-liang, LIU Min, CHEN Qi-min
    2023, 20(11): 3312-3326.
    Rainfall stands out as a critical trigger for landslides, particularly given the intense summer rainfall experienced in Zheduotang, a transitional zone from the southwest edge of Sichuan Basin to Qinghai Tibet Plateau. This area is characterized by adverse geological conditions such as rock piles,debris slopes and unstable slopes. Furthermore, due to the absence of historical rainfall records and landslide inventories, empirical methods are not applicable for the analysis of rainfall-induced landslides. Thus we employ a physically based landslide susceptibility analysis model by using highprecision unmanned aerial vehicle(UAV)photogrammetry, field boreholes and long short term memory(LSTM) neural network to obtain regional topography, soil properties, and rainfall parameters.We applied the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability(TRIGRS) model to simulate the distribution of shallow landslides and variations in porewater pressure across the region under different rainfall intensities and three rainfall patterns(advanced, uniform, and delayed). The landslides caused by advanced rainfall pattern mostly occurred in the first 12 hours, but the landslides caused by delayed rainfall pattern mostly occurred in the last 12 hours. However, all the three rainfall patterns yielded landslide susceptibility zones categorized as high(1.16%), medium(8.06%), and low(90.78%). Furthermore, total precipitation with a rainfall intensity of 35 mm/h for 1 hour was less than that with a rainfall intensity of 1.775 mm/h for 24hours, but the areas with high and medium susceptibility increased by 3.1%. This study combines UAV photogrammetry and LSTM neural networks to obtain more accurate input data for the TRIGRS model, offering an effective approach for predicting rainfall-induced shallow landslides in regions lacking historical rainfall records and landslide inventories.
  • Ciro SEPE, Domenico CALCATERRA, Emilia DAMIANO, Diego DI MARTIRE, Roberto GRECO, Lucia PAPPALARDO, Massimo RAMONDINI, Enza VITALE, Giacomo RUSSO
    2023, 20(11): 3327-3342.
    Fallout volcanic deposits of SommaVesuvius(Campania, southern Italy), characterized by the presence of layers with contrasting textural and hydraulic properties, are frequently affected by shallow landslides during rainwater infiltration. The soils of the stratigraphic sequence present intraparticle pores, originated by the gases escaped during magma decompression in the volcanic conduit, thus are characterized by double porosity(i.e., intraparticle and interparticle pores), which is expected to affect their hydraulic behaviour, and to play a key role in rainwater infiltration through layered deposits. To understand the effect of double porosity on the hydraulic behaviour of the involved soils, controlled experiments have been carried out in an infiltration column. The experimental apparatus is provided with newly designed non-invasive Time Domain Reflectometry(TDR) probes, not buried in the investigated soil layers so as to minimize disturbance to the flow, allowing water content measurement during vertical flow processes. Specifically, transient flow experiments are carried out through reconstituted specimens of black scoriae and grey pumices, both loose pyroclastic granular soils from fallout deposits of Somma-Vesuvius, featuring double porosity with different pore size distributions, that were estimated by X-ray tomography and Mercury Intrusion Porosimetry. The experimental results highlight the effects of the double porosity and clearly indicate the different behaviour of the two soils during wetting and drying processes, mainly related to the different dimensions of intraparticle pores.
  • LIU Qing, WU Ting-ting, DENG Ya-hong, LIU Zhi-heng
    2023, 20(11): 3343-3359.
    Loess landslides are one of the geological hazards prevalent in mountainous areas of Loess Plateau, seriously threatening people's lives and property safety. Accurate identification of landslides is a prerequisite for reducing the risk of landslide hazards. Traditional landslide interpretation methods often have the disadvantage of being laborious and difficult to use on a large scale compared with the recently developed deep learning-based landslide detection methods. In this study, we propose an improved deep learning model, landslide detectionyou only look once(LD-YOLO), based on the existing you only look once(YOLO) model for the intelligent identification of old and new landslides in loess areas.Specifically, remote sensing images of landslides in Baoji City, Shaanxi Province, China are acquired from the Google Earth Engine platform. The landslide images of Baoji City(excluding Qianyang County) are used to establish a loess landslide dataset for training the model. The landslide data of Qianyang County is used to verify the detection performance of the model.The focal and efficient IoU(Focal-EIoU) loss function and efficient channel attention(ECA) mechanism are incorporated into the 7th version of YOLO(YOLOv7)model to construct the LD-YOLO model, which makes it more suitable for the landslide detection task. The experiments yielded an improved LD-YOLO model with average precision of 92.05%, precision of 92.31%, recall of 90.28%, and F1-score of 91.28% for loess landslide detection. The landslides in Qianyang County were divided into two test sets, new landslides and old landslides, which were used to test the detection performance of LD-YOLO for both types of landslides. The results show that LD-YOLO detects old landslides with a detection precision of 82.75%and a recall of 80%. When detecting new landslides,the detection precision is 94.29% and the recall is 91.67%. It indicates that our proposed LD-YOLO model has strong detection performance for both new and old landslides in loess areas. Through a proposed solution that can realize the accurate detection of landslides in loess areas, this paper provides a valuable reference for the application of deep learning methods in landslide identification.
  • ZHANG Yu-Qing, WANG Yue-Lin, LI Hong, LI Xue-Ming
    2023, 20(11): 3360-3375.
    As an important site for tourism activities,mountainous areas may generate greater tourism risks than plain areas due to potential natural disasters, social issues, scenic area management, and tourist behavior. Western Sichuan Plateau is mostly mountainous area and tourism is its pillar industry,Therefore, the assessment of the tourism risks on the Western Sichuan Plateau is of academic value and practical significance. In this study, we use statistical and remote sensing data, fishbone diagram, and the entropy weighting method to construct a tourism risk evaluation model and classify risks into different levels, and we also use a geographic information system(GIS) for spatial mapping to quantify and spatialize the results. The objectives are 1) to identify the risk sources in the Western Sichuan Plateau and analyze their causal mechanisms, precisely reveal the distribution of tourism risks in the study area; 2)improve the precision of tourism risk evaluation in scenic areas and analyze the causes and spatial distribution patterns of tourism risks and propose targeted management measures. This study found that the evaluation results of the four elements of hazard, exposure, vulnerability, and disaster prevention and mitigation capacity on the Western Sichuan Plateau showed significant spatial variability,depending on the natural conditions and the quantity difference of tourism resources in different regions. In addition, the tourism risk is low in most areas of the Western Sichuan Plateau, and disaster prevention and mitigation capacity is higher in areas with high tourism risk where attractions are densely populated and tourism is concentrated. Our study can provide a reference for future analyses of tourism risks in mountainous tourist areas such as in China and worldwide.
  • XU Zhi-hua, GUO Ge, SUN Qian-cheng, WANG Quan, ZHANG Guo-dong, YE Run-qing
    2023, 20(11): 3376-3391.
    The staggered distribution of joints and fissures in space constitutes the weak part of any rock mass. The identification of rock mass structural planes and the extraction of characteristic parameters are the basis of rock-mass integrity evaluation, which is very important for analysis of slope stability. The laser scanning technique can be used to acquire the coordinate information pertaining to each point of the structural plane, but large amount of point cloud data,uneven density distribution, and noise point interference make the identification efficiency and accuracy of different types of structural planes limited by point cloud data analysis technology. A new point cloud identification and segmentation algorithm for rock mass structural surfaces is proposed. Based on the distribution states of the original point cloud in different neighborhoods in space, the point clouds are characterized by multi-dimensional eigenvalues and calculated by the robust randomized Hough transform(RRHT). The normal vector difference and the final eigenvalue are proposed for characteristic distinction, and the identification of rock mass structural surfaces is completed through regional growth, which strengthens the difference expression of point clouds. In addition, nearest Voxel downsampling is also introduced in the RRHT calculation, which further reduces the number of sources of neighborhood noises, thereby improving the accuracy and stability of the calculation. The advantages of the method have been verified by laboratory models. The results showed that the proposed method can better achieve the segmentation and statistics of structural planes with interfaces and sharp boundaries. The method works well in the identification of joints, fissures, and other structural planes on Mangshezhai slope in the Three Gorges Reservoir area, China. It can provide a stable and effective technique for the identification and segmentation of rock mass structural planes, which is beneficial in engineering practice.
  • YAN Peng-cheng, ZHAO Yu-ting, LI Guo-dong, WANG Jing-bao, WANG Wen-chang
    2023, 20(11): 3392-3401.
    The problem of mine water source has always been an important hidden danger in mine safety production. The water source under the mine working face may lead to geological disasters, such as mine collapse and water disaster. The research background of mine water source identification involves many fields such as mining production,environmental protection, resource utilization and technological progress. It is a comprehensive and interdisciplinary subject, which helps to improve the safety and sustainability of mine production.Therefore, timely and accurate identification and control of mine water source is very important to ensure mine production safety. Laser-Induced Fluorescence(LIF) technology, characterized by high sensitivity, specificity, and spatial resolution,overcomes the time-consuming nature of traditional chemical methods. In this experiment, sandstone water and old air water were collected from the Huainan mining area as original samples. Five types of mixed water samples were prepared by varying their proportions, in addition to the two original water samples, resulting in a total of seven different water samples for testing. Four preprocessing methods, namely, MinMaxScaler, StandardScaler,Standard Normal Variate(SNV) transformation, and Centering Transformation(CT), were applied to preprocess the original spectral data to reduce noise and interference. CT was determined as the optimal preprocessing method based on class discrimination,data distribution, and data range. To maintain the original data features while reducing the data dimension, including the original spectral data, five sets of data were subjected to Principal Component Analysis(PCA) and Linear Discriminant Analysis(LDA) dimensionality reduction. Through comparing the clustering effect and Fisher's ratio of the first three dimensions, PCA was identified as the optimal dimensionality reduction method. Finally, two neural network models,CT+PCA+CNN and CT+PCA+ResNet, were constructed by combining Convolutional Neural Networks(CNN) and Residual Neural Networks(ResNet), respectively. When selecting the neural network models, the training time, number of iterative parameters, accuracy, and cross-entropy loss function in the classification problem were compared to determine the model best suited for water source data. The results indicated that CT+PCA+ResNet was the optimal approach for water source identification in this study.
  • HUANG Wen-bo, HUANG Da, GAO Yi-kang, LIU Yang, LI Zhao, MENG Qiu-jie
    2023, 20(11): 3402-3422.
    Internal erosion is one of the important factors causing geological disasters.The microstructure of soil can change with seepage erosion, resulting in changes in the hydraulic and mechanical properties of the soil. The evolution of seepage erosion is investigated with X-ray computed tomography(CT) in this study. The change in macropore structure characteristics during the seepage erosion test is quantified and the influence of seepage erosion on soil deformation is analyzed.Moreover, a pore network model(PNM) is established for the specimens and the evolution of the connected pore size characteristics is assessed. The results show that the macropore structure is significantly affected by seepage erosion, especially in terms of the porosity and pore geometry characteristics. The changes in macropore structure characteristics are most obvious in the lower part of the specimen. The influence of seepage erosion on the pore size distribution(PSD)and soil deformation is heterogeneous and closely dependent on the spatial location of the soil.Moreover, seepage erosion enhances macropore connectivity and has a directional impact on macropore orientation. These findings can provide a reference for the theoretical modeling and numerical simulation of the seepage erosion and improve the understanding of the seepage erosion evolution in engineering practice.
  • LI Cheng-sheng, ZHANG Bing-xin, LIU Zhi-jun, KONG Ling-wei, SHU Rong-jun
    2023, 20(11): 3423-3436.
    The mesomechanics of geotechnical materials are closely related to the macromechanical properties, especially the mesoscale evolution of shear bands, which is helpful for understanding the failure mechanism of geotechnical materials. However, there is lack of effective quantitative analysis method for the complex evolution mechanism of threedimensional shear bands. In this work, we used X-ray computed tomography(CT) to reconstruct volume images and used the digital volume correlation(DVC)method to calculate the three-dimensional strain fields of granite residual soil samples at different loading stages. The trend of the failure surface of the shear bands was obtained by the planar fitting method, and the connectivity index was constructed according to the projection characteristics of the shear bands on the failure trend surface. The results support the following findings: the connectivity index of the shear band increases rapidly and then slowly with increasing axial strain, which is characterized by a near 'S' curve. As the stress reaches the peak value,the connectivity index of the shear bands almost exceeds 0.7. The contribution of the new shear band volume to the connectivity of the shear bands becomes increasingly small with increasing axial loading. Affected by quartz grains and stress at the initial stage, the dip angle gradually and finally approaches the included angle of the maximum shear stress from the discrete state with increasing axial loading. The tendency and dip angle of the resulting shear bands are dynamic, and the tendency slightly deflects with increasing loading.