An analysis of oasis stability in arid areas:a case study in the northern slope areas of the Tianshan Mountains

This paper discusses oasis stability at regional scale with a case study in the northern slope areas of the Tianshan Mountains (NSTM). The results showed certain significant aspects. (1) As long as water resources in the oasis keep stable and their utilization efficiency can be maintained or gradually increased, the primary productivity could be continuously increased and the natural primary productivity keeped relatively stable. In this case, it is considered that the oasis is stable and its sustainable development can be achieved at regional scale. (2) Considering the availability of water resources in the oases, the oases on the alluvial-diluvial fans are highly stable. In the alluvial plain downstream of the groundwater overflowing zones the oases are moderately stable and in the lacustrine deltas or dry lacustrine deltas the oases are lowly stable. (3) Enlargement of oases and the increase of water resources and vegetation coverage in the oasis will certainly enhance the 'cold-island effect' of the oasis and increase the stability of oases.

Numerical analysis of stability for mined-out area in multi-field coupling

There were differences between real boundary and blast hole controlling boundary of irregular mined-out area in underground metal mines. There were errors in numerical analysis of stability for goaf, if it was analyzed as regular 3D mined-out area and the influence of coupling stress-seepage-disturbance was not considered adequately. Taking a lead zinc mine as the background, the model was built by the coupling of Surpac and Midas-Gts based on the goaf model precisely measured by CMS.According to seepage stress fundamental equations based on the equivalent continuum mechanical and the theory about equivalent load of dynamic disturbance in deep-hole blasting, the stability of mined-out area under multi-field coupling of stress-seepage-dynamic disturbance was numerically analyzed. The results show that it is more consistent between the numerical analysis model based on the real model of irregular 3D shape goaf and the real situation, which could faithfully reappear the change rule of stress–strain about the surrounding rock under synthetic action of blasting dynamic loading and the seepage pressure. The mined-out area multi-field coupling formed by blasting excavation is stable. Based on combination of the advantages of the CMS,Surpac and Midas-Gts, and fully consideration of the effects of multi-field coupling, the accurate and effective way could be provided for numerical analysis of stability for mined-out area.

Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area

Dynamic analysis steps and general flow of fast lagrangian analysis of continua in 3 dimensions(FLAC3D) were discussed. Numerical simulation for influence of excavation and blasting vibration on stability of mined-out area was carried out with FLAC3D. The whole analytical process was divided into two steps, including the static analysis and the dynamic analysis which were used to simulate the influence of excavation process and blasting vibration respectively. The results show that the shape of right upper boundary is extremely irregular after excavation, and stress concentration occurs at many places and higher tensile stress appears. The maximum tensile stress is higher than the tensile strength of rock mass, and surrounding rock of right roof will be damaged with tension fracture. The maximum displacement of surrounding rock is 4.75 mm after excavation. However, the maximum displacement increases to 5.47 mm after the blasting dynamic load is applied. And the covering area of plastic zones expands obviously, especially at the foot of right upper slope. The analytical results are in basic accordance with the observed results on the whole. Damage and disturbance on surrounding rock to some degree are caused by excavation, while blasting dynamic load increases the possibility of occurrence of dynamic instability and destruction further. So the effective supporting and vibration reducing measures should be taken during mining.

OPTIMAL HARVESTING AND STABILITY FOR FISHING MODELS WITH STAGE STRUCTURE IN INSHORE-OFFSHORE AREAS

A fishing model with stage structure in inshore and offshore areas is considered.Steady states of the dynamical system representing fishery are derived and their local,as well as global,stability is discussed.The optimal harvest policy is formulated and solved as an optimal control problem.A numerical example is given to illustrate the solution procedure.

Ground stability of new surface buildings erected on site above worked-out area

The subsided area caused by mining is expanding gradually in coal mining areas. In order to occupy less or no farmland, many mining areas are constructing or intend to erect new buildings (structures) on the ground sites above the worked-out areas. The long-term safety of the new buildings is of great importance. This matter should be, therefore, handled with great care. Following an analysis of the different conditions of the worked-out areas, and the characteristics of the failure of different types of worked-out areas and their overlying strata, the cause for the occurrence of residual deformation of the surface above the worked-out area was explained. The techniques for (evaluating) the stability of ground site for erecting new buildings above worked-out area, and the technical measures for protecting such buildings were proposed. The ground stability evaluation techniques were introduced by reference to specific cases.

Stability and Ecological Effects of Main Plant Communities in Minqin Desert Area

[ Objective ] To elucidate the change trend in stability and ecological effects of plant communities in desert along with global wanning. [ Method ] The data of site-specific observation on five main plant communities at ten plots in Minqin desert area were used to analyze the stability and ecological effects of desert plant communities by using two indicators vegetation coverage and projective cover degree. [ Results ] The vegetation coverage of Artemisia arenaria and Ephedra przewalskii, and the projective cover degree of A. arenaria and man-made Haloxylon ammodendron forest decreased remarkably; and the vegetation coverage of Ni- traria tangutorum was also decreased to some extent. [ Conduslon] （1） The plant communities with poor vegetation coverage gives a relatively strong stability, while that with high vegetation coverage has a relatively poor stability; （2） the yearly precipitation is the determinant of vegetation coverage and projective cover deglee; （3） the ecological function is found to be most remarkable in per unit area N. tangutorum, followed by E. przewalskii and N. tangutorum ＋H. ammodendron, and least in per unit area A. Arenaria. The vegetation is sparse in desert and plant branches does not distribute regularly, thus the crown-based vegetation coverage can not reflect the actual surface coverage.

Factors that Affect Social Stability of Rural Areas in Ganzi District

Through the sample investigation of Kangding County, Daofu County, Luhuo County and Xiangcheng County in Sichuan Province in 2010 and by combining the quantitative and qualitative methods, various kinds of indexes from the aspects of society, politics, economy and values in Ganzi District are analyzed, as well as the factors that affect the rural social stability of current Ganzi District area. The results show that rural areas of Ganzi District are stable on the whole, but the economic development level is backward; the social security measures are imperfect; disputes among rural residents still exist and most of them are economic disputes; the disputes among ethnics are mainly caused by religious belief; the autonomous situation of partial rural residents are bad and rural residents' evaluation on social justice is low. Therefore, it should establish and perfect relevant prevention and control mechanism.

Engineering Geological Study of Regional Tectonic Stability in the Area of the Longyang Gorge Power Station on the Huanghe (Yellow) River

In the stability study of the regional structures in the area of the Longyang Gorge Hydroelectrical Power Station, a model of the current stress-deformation field of the area was constructed based on analyses of available data of regional surveys and historical earthquakes and field investigations of active faults and ancient earthquakes. This model was examined and verified by physical and mathematical simulation experiments, and quantitative relations and data were obtained.

Stability Analysis and Measure Study of Tobacco Farmers in the Mountainous Area of Western Hubei

Through the investigation,this paper analyzes the important restricting factors for the tobacco farmers in Enshi Badong mountainous area from 2018 to 2021,including the age structure,the loss situation,the number of years of planting tobacco,the scale of planting tobacco and the benefit of planting tobacco.This paper puts forward some corresponding measures and suggestions,such as cultivating the team of professional tobacco farmers,establishing the team of young tobacco farmers,expanding professional services,developing"tobacco plus"diversified industries,and popularizing suitable agricultural machinery in mountainous areas in order to effectively improve the stability of the team of tobacco farmers.

Stability Analysis of a Multi Area System with Renewable Energy and Multi-Terminal DC Tie Lines

Security constrained multi area multi objective dynamic economic dispatch (SCMAMODED) with renewable energy (RE) and all the possible MTDC stability constraints is formulated for the first time. The stability merits of multi terminal DC (MTDC) tie lines as compared to the traditional HVAC forms the main objective of this paper. Probabilistic load flow (PLF) is applied to determine the system parameters while the uncertainties are modelled using Scenario Based Method (SBM). The simulation results reveal that with the use of MTDC tie lines, the frequency and voltage stability in the MAMODED with renewable energy sources (RES) are enhanced while keeping the MTDC power exchange interface nodes at secure levels.

RESEARCH ON THE COLLOID MATERIALS FOR STOPE STABILITY SIMULATION

Applying statistics and the orthogonal experiment design method, this paper studies the colloid materials for stope stability simulation and gets some material blending ratios to meet demands of original models to obtain satisfactory reliability.

Catastrophe analysis on pillar instability considered mining effect

The instability of the pillar was discussed based on the potential energy principle and the cusp catastrophe theory, and a simplified mechanical model of the pillar was established considering the mining effect. The necessary-sufficient conditions, the jump value of displacement of pillar and the released energy expressions were deduced. The results show that the instability of the pillar is related to the properties of the rock, the external force and the relative stiffness of the elastic area to the plastic area. The instability of system is like to occur with the enlarging of the softening area or the decreasing of E/λ. The calculation done shows that the estimated results correspond to practical experience.

Langmuir films stability phenomenon of glycerol dialkyl nonitol tetraether at the air-water interface for variations spreading time

Langmuir films behavior of asymmetric glycerol dialkyl nonitol tetraether (GDNT) lipids at the air-water interface (temperature 19℃ ± 1℃) investigated the stability of the mean ratio of Langmuir films for different spreading time prior to the transfer film. Floating monolayer films stability is an important parameter to obtain high-quality Langmuir-Blodgett films for their aplications. Hysteresis loop of the compression-decompression (μ-A) isotherms of Langmuir film GDNT used to analyze the thermodynamic stability of the monolayer films and its features. Langmuir films stability of tetraether lipid GDNT shown more stable at the time of spreading longer than a short time.

Comparison and Performance Analysis of FACTs Controller in System Stability

In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.

锦州市规划区地质环境安全评价研究

地质环境问题是影响城市国土空间安全开发利用的重要因素,在城市规划开发阶段开展地质环境综合评价可有效控制地质灾害风险。锦州市规划区尚处于开发前期,本文基于该规划区的地质条件和开发需求,构建了地质环境安全评价指标和评价方法体系,基于主导因素综合法开展了地质环境安全综合评价。根据评价结果,锦州市规划区地质环境安全程度可划分为3级,空间分布上以相对安全区为主,其次为次不安全区和安全区。按照空间位置和区域构造稳定性、地质灾害易发性等不同成因划分为23个亚区,并指出了每个亚区安全程度主要影响因素。该评价结果反映了锦州市规划区的地质环境安全程度,确定了影响地质环境安全问题的关键因素,有助于规避该区国土空间规划开发可能面临的地质灾害风险。

安徽琅琊山风景区某崩塌的特征分析及治理措施

【目的】分析安徽琅琊山风景区某崩塌隐患点的特征并提出治理措施。【方法】采用现场调研、地形测绘、三维激光扫描仪、稳定性评价等手段,获得该崩塌点的特征和稳定性。【结果】该崩塌点具备倾倒式崩塌的特征,4个主要危岩体都是处于不稳定或欠稳定状态。【结论】采用设置锚杆、支撑墙、水泥浆充填等方法对危岩体进行加固,并采用人工清除松动石块、发挥截水沟的作用等方法进行治理,能够消除崩塌隐患,确保景点安全和景观价值。

煤矿采动稳定区煤层气开发区块经济评价技术

针对我国煤矿采动稳定区煤层气开发区块评价技术缺乏,难以有效指导经济开发应用这一问题,基于煤层气开发效果与综合效益,分析了采动稳定区煤层气开发区块评价关键参数,构建了考虑技术进步等动态影响因素的煤层气开发区块经济评价指标体系,采用层次分析方法获得了各单项指标的相对权重,并提出了开发区块最大隶属原则经济评价方法。应用试验表明,该经济评价方法可为煤矿采动稳定区煤层气开发决策提供可靠指导。

某金矿多中段充填开采对地表塌陷区稳定性影响分析

随着矿井开采逐步向深部发展,多中段开采引起的围岩稳定问题是矿井面临的主要安全因素。某金矿开采分为早期浅部空场法开采和后期深部充填开采两个阶段,早期开采在地表形成了一定范围的塌陷区。为了掌握深部多中段充填开采的覆岩移动变形叠加效应是否引起浅部塌陷区的活化,进而影响地表稳定性及井下安全生产,首先,采用理论分析方法研究了浅部塌陷区形成原因、机理,进而分析了地表塌陷区当前的自身稳定性;然后,采用RHINO、FLAC3D等数值模拟方法研究了深部上向水平分层充填开采引起的围岩移动变形规律及其引起的地表塌陷区的剩余沉降和塑性区发育。研究认为,某金矿深部多中段充填开采后充填区自身的变形量、浅部采空区内部岩层位移及地表沉降整体较小,相比于未充填情况下可较大程度减小围岩变形和地表塌陷区沉降,地表塌陷区仅在局部区域出现塑性区,多中段充填开采在维持当前充填效果的前提下不影响地表塌陷区的整体稳定性。本文研究方法及成果可为金属矿山充填开采覆岩变形安全性评价及地表塌陷区灾害防治提供有益借鉴。

武汉城市圈生态网络鲁棒性模拟及稳定性分析

生态网络在不同破坏程度或干扰强度下呈现出不同的鲁棒性,势必造成区域生态系统的稳定性风险。基于武汉城市圈生态网络的构建与识别,建立节点和廊道的重要性评价体系,运用鲁棒模型模拟随机干扰情景下的鲁棒性变化评价生态网络的稳定性特征。结果表明:基于复杂网络理论对武汉城市圈生态网络进行拓扑网络提取,共生成117个节点和189条连接线,重要性等级较高的节点占23.9%,主要分布在研究区中北部区域,重要性较低的节点占节点总数的51.3%,主要分布在研究区的西北和东南地区;采用重力模型判别生态廊道重要性,得到17条重要廊道,28条一般廊道,重要廊道对生态网络的连通性和稳定性具有极大影响;节点数量和重要度对网络的稳定性具有显著影响,当节点失效率低于50%时,生态网络稳定性变化较小,整体处于较高的稳定性;当节点失效率在50%—85%时,生态网络极其不稳定;当节点失效比率达到85%时,生态网络开始瘫痪;依据生态节点和廊道的重要性以及模拟结果,分别提出生态节点保护和廊道建设的差异化管理策略。

安徽省宁国市山核桃种植区典型滑坡机制与稳定性分析——以石岭村滑坡为例

宁国山核桃种植区环境地质条件复杂,人类活动活跃,降雨充沛,是安徽省滑坡灾害极高易发区之一。选择种植区东部石岭村滑坡为研究对象,采用遥感、地形测量、地质勘查等工作手段,对滑坡的变形特征、形成条件、破坏机制及稳定性等特征进行详细研究,并提出防治建议。研究结果表明:石岭村滑坡为一受基覆界面控制的小型复合式土质滑坡,在工况Ⅱ(自重+持续暴雨)下稳定系数为0.8543(不稳定),处于蠕变状态,复活的可能性较大;其主控因素为软弱的岩土体结构和适宜的地形地貌条件,诱发因素为强降雨和人类工程活动;建议对种植区自然斜坡进行工程治理,同时改变山核桃采摘方式(如采用低空挂网兜拾),恢复植被,减少水土流失。研究成果可为种植区滑坡灾害早期识别和防治等提供重要借鉴。