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An novel energy dissipator with self-recovery capability after deformation for structurally energy-dissipating rock-shed

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Journal of mountain Science 2021年第11期18卷 3058-3068页

作者： XIE Qi-jun SU Li-jun BAI Hao TANG Hao {2. Chong-lei YU Fang-wei Key Laboratory of mountain hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China sichuan Expressway Construction&Development Group CO. LTD.Chengdu 610041China China-Pakistan joint Research Center on Earth sciences CAS-HECIslamabad 45320Pakistan University of chinese academy of sciences Beijing 100049China College of environment and Civil Engineering in chengdu University of Technology Chengdu 610051China

Theperformanceof a structurally dissipating rock-shed(SDR)depends largely onthecapacityofitsenergy *** present,mostenergy dissipatorsare made of metals,which dissipateenergy by unrecoverable plastic ***,they are not able to recover their energy-dissipation capacity after deformation under rockfall ***,a rockfall usually disintegrates into pieces when it rolls down from a higher position and results in multiple rockfall *** energy dissipator with self-recovery capability is therefore more suitable for ensuring the safety of *** metal with polyurethane(a hyperelastic material with remarkable self-recovery capability)can provide self-recovery capability for energy dissipators,making them more suitable for resisting multiple rockfall *** this work,polyurethane was manufactured into twotypes ofenergy dissipators:cylindrical and ***-scale falling rock impact testsand dynamic numerical simulationswereconducted to study the mechanical response of the energy *** addition,in order to ensure the accuracy of the simulation,the dynamic mechanical properties of the polyurethanewere tested and its dynamic constitutive model was *** experimental and simulation tests have clarified the advantages of the polyurethane energy *** also summarized the practical considerations in the design of energy dissipators.

关键词： Recoverableenergy dissipator Dynamic constitutive model Rockfall test Numerical simulation Resist multiple impacts

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Wind erodibility indices of aeolian sandy soils impacted by different vegetation restoration:a case study from the Shannan valley of the Yarlung Zangbo River

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Journal of mountain Science 2022年第10期19卷 2830-2845页

作者： zhang Bao-jun XIONG Dong-hong LIU Lin TANG Yong-fa Key Laboratory of mountain hazards and Earth Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China College of Water Conservancy and Hydropower Engineering Sichuan Agricultural UniversityYa'an 625014China

Controlling aeolian desertification is a key ecological target on the Tibetan Plateau,especially within the widespread river *** recovery can change the near-soil surface characteristics,which thus may influence wind erodibility of ***,these potential effects are not sufficiently evaluated for aeolian sandy *** study selected the Shannan valley of the Yarlung Zangbo River on the southern Tibetan Plateau as a case to investigate the variations in wind erodibility of aeolian sandy soils impacted by different vegetation restoration,since many ecological measures have been implemented in recent decades in the river *** vegetated sandy lands with different restoration types and ages and two bare sandy lands(as controls)were chosen as test *** vegetated sandy lands were covered by Artemisia wellbyi,Hedysarum scoparium,Sophora moorcroftiana,and Populus *** the similar restoration age of 10 *** Sophora moorcroftiana and Populus ***,two restoration ages of 6 and over 30 years were also selected *** erodibility was reflected by wind erodible fraction(EF),mean weight diameter of dry aggregates(MWD),capillary water capacity(CWC),soil cohesion(CS),and soil penetration resistance(PR)from different aspects.A comprehensive wind erodibility index(CWEI)was further produced by a weighted summation method to combine those five indices together and comprehensively quantify the effects of vegetation restoration on wind erodibility of aeolian sandy *** results showed that revegetation was efficient to reduce wind erodibility of aeolian sandy *** generally decreased,while MWD,CWC,CS,and PR increased after vegetation restoration on the aeolian sandy *** CWEI of vegetated sandy lands varied greatly from 0.850 to 0 under different restoration types and ages and decreased by 14.4%to 100%compared to the *** the four different restoration types,Populus *** the relatively minimum CWEI,fol

关键词： Wind erosion Soil erodibility Erodible fraction Vegetation type Ecological restoration Yarlung Zangbo River valley

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A multiobjective evolutionary optimization method based critical rainfall thresholds for debris flows initiation

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Journal of mountain Science 2020年第8期17卷 1860-1873页

作者： YAN Yan zhang Yu HU Wang GUO Xiao-jun MA Chao WANG Zi-ang zhang Qun Key Laboratory of High-Speed Railway Engineering MOE/School of Civil EngineeringSouthwest Jiao tong UniversityChengdu 610031China institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Key Laboratory of mountain Surface Process and hazards/{2. of mountain hazards and environment Chinese Academy of SciencesChengdu 610041China School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China sichuan institute of Land and Space Ecological Restoration and Geological Hazard Prevention Chengdu 610081China

At present,most researches on the critical rainfall threshold of debris flow initiation use a linear model obtained through *** relatively weak fault tolerance,this method not only ignores nonlinear effects but also is susceptible to singular noise samples,which makes it difficult to characterize the true quantization relationship of the rainfall ***,the early warning threshold determined by statistical parameters is susceptible to negative samples(samples where no debris flow has occurred),which leads to uncertainty in the reliability of the early warning results by the regression *** overcome the above limitations,this study develops a data-driven multiobjective evolutionary optimization method that combines an artificial neural network(ANN)and a multiobjective evolutionary optimization implemented by particle swarm optimization(PSO).Firstly,the Pareto optimality method is used to represent the nonlinear and conflicting critical thresholds for the rainfall intensity I and the rainfall duration *** ANN is used to construct a dual-target(dual-task)predictive surrogate model,and then a PSO-based multiobjective evolutionary optimization algorithm is applied to train the ANN and stochastically search the trained ANN for obtaining the Pareto front of the I-D surrogate prediction model,which is intended to overcome the limitations of the existing linear regression-based threshold ***,a double early warning curve model that can effectively control the false alarm rate and negative alarm rate of hazard warnings are proposed based on the decision space and target space *** study provides theoretical guidance for the early warning and forecasting of debris flows and has strong applicability.

关键词： Debris flow Critical rainfall thresholds Multiobjective evolutionary optimization Artificial neural network Pareto optimality

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A modified TOPMODEL introducing the bedrock surface topographic index in Huangbengliu watershed,China

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Journal of mountain Science 2022年第12期19卷 3517-3532页

作者： QIU An-ni zhang Yan-jun WANG Gen-xu CUI jun-fang SONG Yuan-xin SUN Xiang-yang CHEN Li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China State Key Laboratory of Hydraulics and mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China institute of mountain {2. and environment Chinese Academy of SciencesChengdu 610041China Key laboratory of Hydrometeorological Simulation Prediction and WarningNanjing University of Information Science and TechnologyNanjing210044China School of Hydrology and Water Resources Nanjing University of Information Scienceand TechnologyNanjing 210044China

Subsurface stormflow is a dominant runoff mechanism in steep humid mountainous *** insite measurement of subsurface stormflow suggests that the bedrock surface plays an important role in the runoff generation and routing process,which was rarely adopted in hydrological modelling *** improve the runoff simulation performance,the bedrock surface topographic index is introduced,and a modified TOPMODEL based on the bedrock surface topographic index is developed to simulate the *** modified TOPMODEL is applied to the Huangbengliu(HBL),a steep watershed in Gongga mountain,and proved to be more appropriate for the HBL watershed,especially for peak *** Nash-Sutcliffe model efficiency(NSE)is improved from 0.2. to 0.58 in the calibration period and from 0.40 to 0.62.in the verification *** result of this study can advance the understanding of the mechanism of flash floods and contribute flood control and disaster prevention in the HBL watershed and similar areas.

关键词： Subsurface stormflow Flash flood Modified TOPMODEL Bedrock surface topographic index Gongga mountain

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Effect of cement on the stabilization of loess

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Journal of mountain Science 2017年第11期14卷 2325-2336页

作者： zhang Chong-lei JIANG Guan-lu SU Li-jun ZHOU Gong-dan Key Laboratory of mountain hazards and Earth Surface Processes Institute of Mountain Hazards and Environment Chinese Academy of Sciences Key Laboratory of High-speed Railway Engineering of Ministry of Education School of Civil Engineering Southwest Jiaotong University CAS Center for Excellence in Tibetan Plateau Earth sciences University of chinese academy of sciences

Considering the potential use of cementstabilized loess(CSL) as a construction material for structures that are subjected to frequent loess landslides, this paper explores the stabilization and improvement of geotechnical characteristics of loess achieved by the addition of 0%-9% cement by dry weight. Laboratory evaluations investigated the consistency limits, compaction, compressibility, California bearing ratio(CBR), direct shear strength, and unconfined compression strength(UCS) of CSL for different curing stages. A durability index was quantified to estimate the influence of wetting-drying(w-d) cycles on CSL strength, and an optimum cement dosage was also identified. The results reveal that the cohesion of CSL is substantially more sensitive to structure than its friction angle and that cohesion is responsible for shear strength increase after remoulding. The cement proportions have an effective role in the enhancement of compressibility. The development of UCS can be categorized into the early stage(14 days) and the later stage(>14 days). The increase in strength primarily occurred in the first 14 days. The w-d cycles have a significantinfluence on the decrease in compression strength. The CBR value increases with increments of additional proportions and compaction times. The relationships of UCS versus the compressibility modulus and UCS versus CBR are established to facilitate the mix design for strength. A rational predictive exponential equation is proposed to predict the durability index for different w-d cycles.

关键词： Landslide Cement Loess stabilization Durability index Wetting-drying cycle

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Dynamic behaviour of weathered red mudstone in sichuan(China)under triaxial cyclic loading

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Journal of mountain Science 2018年第8期15卷 1789-1806页

作者： zhang Chong-lei JIANG Guan-lu SU Li-jun LIU Wei-ming Key Laboratory of mountain hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Ministry of Education Key Laboratory of High-speed Railway EngineeringSchool of Civil EngineeringSouthwest Jiaotong UniversityChengdu 610031China. CAS Center for Excellence in Tibetan Plateau Earth sciences Beijing 100101China University of chinese academy of sciences Beijing 100049China

The construction of a high-speed railway(HSR) in Southwest China is being hindered by a severe shortage of high-quality subgrade materials. However, red mudstone is widely distributed in the sichuan Basin of China. The ability to use weathered red mudstone(WRM) to fill subgrade beds by controlling its critical stress and cumulative strain would enable substantial savings in project investments and mitigate damage to the ecological environment. To better understand the dynamic behaviour of WRM, both monotonic and cyclic triaxial tests were performed. The evolution of the cumulative strain vs. increased loading cycles was measured. The influences of confining pressure and loading cycles on the dynamic modulus, damping ratio, critical cyclic stress ratio(CSR), and dynamic stress level(DSL) were investigated. The relationship between the CSR and loading cycles under diffe{2.t failure strain criteria(0.1%-1.0%) was analysed. The prediction model of cumulative strain was also evaluated. The results indicated that the shear st{2.gth of WRM sufficiently meets the static st{2.gth requirements of subgrade. The critical dynamic stress of WRM can thus satisfy the dynamic stress-bearing requirement of the HSR subgrade. The critical CSR decreases and displays a power function with increasing confining pressure. As the confining pressure increases, the DSL remains relatively stable, ranging between 0.153 and 0.163. Furthermore, the relationship between the dynamic st{2.gth and loading cycles required to cause failure was established. Finally, a newly developed model for determining cumulative strain was established. A prediction exercise showed that the model is in good agreement with the experimental data.

关键词： Cyclic triaxial tests Cyclic stress ratio Red mudstone Critical dynamic stress Cumulative strain Railway subgrade

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Adjusting precipitation measurements from the TRwS2.4 automatic weighing gauge in the Qilian mountains, China

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Journal of mountain Science 2018年第11期15卷 2365-2377页

作者： ZHENG Qin CHEN ren-sheng HAN Chun-tan LIU jun-feng SONG Yao-xuan LIU {2.-wen YANG Yong WANG Lei WANG Xi-qiang LIU Xiao-jiao GUO Shu-hai LIU Guo-hua Qilian Alpine Ecology and Hydrology Research Station Key Laboratory of Ecohydrology of Inland River BasinNorthwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China University of chinese academy of sciences Beijing 100049 China

With the popularity of the automatic precipitation gauges in national weather stations,testing their performance and adjusting their measurements are top priorities. Additionally,because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Altershielded TRwS2.4 automatic weighing gauge(TRwS_(SA)) relative to the adjusted manual measurements(reference precipitation) from the chinese standard precipitation gauge in a doublefence wind shield(CSPG_(DF)) in the Hulu watershed in the Qilian mountains, China. The measurements were compared over the period from August {2. to July{2., and the transfer function derived from the work by Kochendorfer et al.({2. a) for correcting windinduced losses was applied to the TRwS_(SA) measurements. The results show that the average loss of TRwS_(SA) measurements relative to the reference precipitation decreased from 0.55 mm(10.7%) to 0.51 mm(9.9%) for rainfall events, from 0.35 mm(8.5%)to 0.2. mm(5.3%) for sleet events, and from 0.49 mm(18.9%) to 0.33 mm(12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwS_(SA) measurements are considered to be mainly caused by specific errors of TRwS_(SA), different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.

关键词： TRwS2.4 automatic weighing gauge chinese standard precipitation gauge Adjusting precipitation measurements Qilian mountains

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Directional seismic response to the complex topography:A case study of 2.1. Lushan Ms 7.0 earthquake

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Journal of mountain Science 2020年第9期17卷 2049-2067页

作者： ZHAO Bo WANG Yun-sheng SU Li-jun LUO Yong-hong zhang Jing Key Laboratory of mountain hazards and Earth Surface Processes Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China CAS Center for Excellence in Tibetan Plateau Earth sciences Beijing 100101China China-Pakistan Joint Research Center on Earth sciences Islamabad 30001Pakistan University of chinese academy of sciences Beijing 100049China

Azimuthal variations in site response can provide a good insight into the site amplification and seismic conditions of geohazard *** this study,multiple directional site response methods,including D-Arias(Directional-Arias),D-SER(Directional-Shaking energy ratio),D-HVSR(Directional-Horizontal to vertical spectral ratio)and D-SSR(Directional–Standard spectral ratio),are adopted to analyse seismic data of the 2.1. Lushan Ms 7.0 earthquake captured by the self-established Lengzhuguan(LZG)station which consists of the complex topography of isolated ridge,large mountain and some typical *** results show that the isolated ridge could cause stronger site responses than the large mountain,and whose pronounced response direction is roughly perpendicular to its *** the growth of elevation,the siteresonant frequency *** different microreliefs on the mountain cause different site responses,which present as protruding slope>linear *** site response mainly exists on the surficial layer of the mountain and shows that with the increase of the distance to mountain surface,the site response gets weaker,the site resonant frequency gets higher,and the pronounced response direction is perpendicular to its ridgeline.

关键词： Site response Pronounced response direction LZG station Lushan Ms 7.0 earthquake

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Novel models for simulating maize growth based on thermal time and photothermal units: Applications under various mulching practices

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Journal of Integrative Agriculture 2023年第5期22卷 1381-1395页

作者： LIAO Zhen-qi ZHENG Jing FAN jun-liang PEI Sheng-zhao DAI Yu-long zhang Fu-cang LI Zhi-jun Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas Ministry of EducationNorthwest A&F UniversityYangling 712100P.R.China institute of mountain {2. and environment Chinese Academy of SciencesChengdu 610041P.R.China

Maize (Zea mays L.) is one of the three major food crops and an important source of carbohydrates for maintaining food security around the *** height (H),stem diameter (SD),leaf area index (LAI) and dry matter (DM) are important growth parameters that influence maize ***,the combined effect of temperature and light on maize growth is rarely considered in crop growth *** maize growth models based on the modified logistic growth equation (Mlog) and the Mitscherlich growth equation (Mit) were proposed to simulate the H,SD,LAI and DM of maize under different mulching practices based on experimental data from 2.1.–*** the accumulative growing degree-days (AGDD),helio thermal units (HTU),photothermal units (PTU) or photoperiod thermal units (PPTU,first proposed here) was used as a single driving factor in the models;or AGDD was combined with either accumulative actual solar hours (ASS),accumulative photoperiod response (APR,first proposed here) or accumulative maximum possible sunshine hours (ADL) as the dual driving factors in the *** model performances were evaluated using seven statistical indicators and a global performance *** results showed that the three mulching practices significantly increased the maize growth rates and the maximum values of the growth curves compared with *** the four single factor-driven models,the overall performance of the Mlog_(PTU)Model was the best,followed by the Mlog_(AGDD)*** Mlog_(PPTU)Model was better than the Mlog_(AGDD)Model in simulating SD and *** the 10 models,the overall performance of the Mlog_(AGDD–APR)Model was the best,followed by the Mlog_(AGDD–ASS)***,the Mlog_(AGDD–APR)Model performed the best in simulating H and LAI,while the Mlog_(AGDD–ADL)and Mlog_(AGDD–ASS)models performed the best in simulating SD and DM,*** conclusion,the modified logistic growth equations with AGDD and either APR,ASS or ADL as the dual driving

关键词： thermal time accumulative growing degree-days helio thermal units photothermal units growth model

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Effects of vegetation coverage and seasonal change on soil microbial biomass and community structure in the dry-hot valley region

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Journal of mountain Science 2018年第7期15卷 1546-1558页

作者： WU Han XIONG Dong-hong XIAO Liang zhang Su YUAN Yong SU Zheng-an zhang Bao-{2. YANG Dan Key Laboratory of mountain hazards and Earth Surface Processes Institute of Mountain Hazards and Environment Chinese Academy of Science Chengdu 610041 China University of chinese academy of sciences Beijing 100049 China

Soil microorganisms are sensitive indicator of soil health and quality. Understanding the effects of vegetation biomass and seasonal change on soil microorganisms is vital to evaluate the soil quality and implement vegetation restoration. This study analyzed the soil phospholipid fatty acids(PLFAs) in fresh and withered Kudzu(Pueraria montana var. lobata) vegetation conditions in different seasons. The results showed that vegetation biomass and seasonal change significantly affected microbial biomass and its community structure. Both fresh and withered Kudzu cover significantly increased soil microbial biomass, and the growth effect of microbes in the soil with fresh Kudzu cover was more obvious than that with withered Kudzu cover. Compared with the dry season, the rainy season significantly increased the microbial biomass and the B/F(the ratio of bacterial to fungal PLFAs) ratio but dramatically reduced the G+/G-(the ratio of gram-positive to gram-negative bacteria PLFAs). Kudzu cover and seasonal change had a significant effect on microbial structure in soil covered by higher vegetation biomass. Furthermore, soil temperature and moisture had different correlations with specific microbial biomass in the two seasons. Our findings highlight the effect of Kudzu vine cover on the soil micro{2. and soil microhabitat, enhancing the soil quality in the Dry-hot Valley of Jinsha River, Southwest China.

关键词： Phospholipid fatty acid Vegetation Soil microbes Soil temperature Soil moisture Dry-hot valley

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