Comparison of Building Damage Assessment Methods for Risk Analysis in Mining Subsidence Regions

The occurrence of subsidence phenomena in urban regions may induce small to severe damage to buildings. Many methods are provided in the literature to assess buildings damage. Most of these methods are empirical and use the horizontal ground strain as a subsidence intensity in the vicinity of a building. Application and comparison of these methods with a case study is the main objective of this paper. This comparison requires some harmonization of the existing methods and the development of a software, which combines the subsidence hazard prediction, the damage evaluation methods and a database of buildings with structural parameters as well as the geographical coordinates of the buildings An additional results is the development of a method for the prediction of the horizontal ground strain in the vicinity of each building. Results are given as a map of damaged buildings for the case study and the different existing methods with some statistical calculations such as the mean and the standard deviation of damage in the city. Comparison of these results allows identification of the “safer” method that give the higher mean of damage. The comparison of the calculated results and observed damage in Lorrain region show that, the Dzegeniuk et al. methods is more realistic in comparison of the other empirical methods.     

泥石流作用下建筑物易损性评价方法分析与评价

建筑物易损度评价作为泥石流易损度评价的重要组成部分,其研究是实现城镇及居民点泥石流风险定量化和风险管理的必要环节。综述近30年来,泥石流作用下建筑物易损度研究的发展过程,并指出以统计分析方法建立的建筑物易损度曲线普适性差且力学机理不明等问题,提出数值计算和模型实验的手段获取建筑物结构易损度的机理模型。由于建筑物易损度研究问题本身的复杂性,统计分析方法仍将作为建筑物易损度研究的重要手段,力学机理明晰的研究方法则将成为今后研究的难点和热点。此外,地震、滚石、雪崩等类似灾种的易损度研究方法和成果可被借鉴到泥石流领域。针对灾害中因结构破坏引发人员伤亡的情况,建议采用时间概率和基于条件概率的事件树方法计算建筑物内人员易损度。最终形成综合结构和人员易损度研究成果的建筑物易损度评价方法。     

Centrifuge modeling of land subsidence caused by the high-rise building group in the soft soil area

With the increase of the high-rise buildings, land subsidence induced by human activities becomes a major problem. Land subsidence occurs slowly, but the accumulation results in the cracks in the road, the damage to the pipelines and in the tilting or the cracking of the buildings. With the withdrawal of groundwater controlled reasonably, the engineering-environmental effect of the dense high-rise building group comes to be the main cause of land subsidence. Based on the high-rise building group in the soft soil area in Shanghai, the mechanism of land subsidence is studied in this paper by the centrifuge model tests. The central area of the building group has larger subsidence and the subsidence superimposition effect is obvious. It can exceed the allowance and cause land subsidence hazard. The land subsidence affected by the different building distances is also studied. For smaller building distances, the subsidence superimposition effect is more obvious. The larger excess pore water pressure in the pile-base supporting layer of the central area shows that the stress superimposition effect is larger. The earth pressure under the buildings fluctuates by the disturbance of the pile tips.     

辽宁省某工业园建设项目中的地质灾害危险性评价

辽宁省某工业园建设用地地处冲海积平原,地形简单,地貌类型单一,地层岩性较复杂,地质环境复杂,该工程项目地质灾害危险性评估等级为一级。区内现状地质灾害不发育;在工程建设过程中和建成后可能引发软土触变所致的地面（地基）不均匀沉降地质灾害,危害建筑物的地面稳定及安全,其危险性为中等级别;工程建设后可能遭受软土触变所致的地面（地基）不均匀沉降,其可能性、危害性、危险性均为中等级别;工程建设本身可能遭受砂土液化地质灾害的可能性、危害性和危险性均为小的级别。针对地面（地基）不均匀沉降地质灾害和砂土液化地质灾害提出了相应的防治措施,对防止地质灾害造成损失和保护生态环境都将具有指导意义。     

Evaporite Dissolution Subsidence in the Historical City of Calatayud,Spain: Damage Appraisal and Prevention

Calatayud in NE Spain is an historically important city built on recent alluvial deposits underlain by gypsum and other soluble rocks. Since its foundation by the Muslims in 716 A.D., the city development has been strongly influenced by geohazards including flooding, subsidence and slope movements. Most of the flooding problems have been mitigated by diversion of the local drainage. However, dissolution of the evaporite bedrock in the urban areas continually causes subsidence and triggers rock-falls from the gypsum cliffs overlooking the city. Subsidence is also caused by the hydrocollapse of gypsiferous silt in the alluvial fan deposits. Building damage in the city was surveyed using a classification scheme developed originally to record damage in British coal mining areas. The Calatayud damage survey shows that the worst building subsidence is concentrated along the line of a buried channel that runs underneath the gypsiferous silt alluvial fan. Natural subsurface drainage causes the dissolution and subsidence, which is aggravated by leakage from water and sewage pipes. Some building damage has been exacerbated during reconstruction by incomplete piling leaving buildings partially unsupported. Mitigation measures include the control of water leakage by the installation of flexible service pipes. Careful construction techniques are needed for both conservation and new developments, especially when piled and minipiled foundations are used. Geomorphological mapping is cost-effective in helping to locate and avoid the zones of subsidence for future development.     

温岭市西部平原地面沉降特征及防治对策

温岭市西部平原是经济活动最为活跃的地区．近20年以来，随着地下水开采量的不断增大，引发了严重的地面沉降，本文通过对不同时期的地形高程对比，分析确定了地面沉降量等特征，研究表明温岭市西部平原始地面高程仅2．5～3．3m，近20年来累计最大沉降量已大于1300mm.已成为浙江省地面沉降最为严重的地区之一，地面沉降导致沉降区内部分民房和耕地被水淹，直接影响到当地群众的生活和生产，本文根据温岭市实际，提出了地面沉降的防治措施和对策。     

苏家里新村地面及建筑物裂缝成因分析

以苏家里新村地面及建筑物裂缝调查结果和沉降监测资料为基础,应用工程地质类比法对非采矿因素引起的裂缝进行综合的定性分析,并应用FLAC3D程序对受煤矿采空区影响的建筑物进行数值模拟分析,同时归纳分析了对由于采矿因素和非采矿因素导致的地面及建筑物裂缝的成因、位置和规律。分析结果表明:苏家里新村地面及建筑物裂缝是开采沉陷引起的地表变形、填土地基不均匀沉降、河流冲蚀边坡坡脚等因素共同作用的结果。研究结果为该矿区地面建筑物的修复加固提供依据。      

Finite-difference model of land subsidence caused by cluster loads in Zhengzhou,China

Groundwater exploitation has been regarded as the main reason for land subsidence in China and thus receives considerable attention from the government and the academic community.Recently,building loads have been identified as another important factor of land subsidence,but researches in this sector have lagged.The effect of a single building load on land subsidence was neglected in many cases owing to the narrow scope and the limited depth of the additional stress in stratum.However,due to the superposition of stresses between buildings,the additional stress of cluster loads is greater than that of a single building load under the same condition,so that the land subsidence caused by cluster loads cannot be neglected.Taking Shamen village in the north of Zhengzhou,China,as an example,a finite-difference model based on the Biot consolidation theory to calculate the land subsidence caused by cluster loads was established in this paper.Cluster loads present the characteristics of large-area loads,and the land subsidence caused by cluster loads can have multiple primary consolidation processes due to the stress superposition of different buildings was shown by the simulation results.Pore water migration distances are longer when the cluster loads with high plot ratio are imposed,so that consolidation takes longer time.The higher the plot ratio is,the deeper the effective deformation is,and thus the greater the land subsidence is.A higher plot ratio also increases the contribution that the deeper stratigraphic layers make to land subsidence.Contrary to the calculated results of land subsidence caused by cluster loads and groundwater recession,the percentage of settlement caused by cluster loads in the total settlement was 49.43%and 55.06%at two simulated monitoring points,respectively.These data suggest that the cluster loads can be one of the main causes of land subsidence.     

Field-observed phenomena of seismic liquefaction and subsidence during the 2008 Wenchuan earthquake in China

In the 2008 Wenchuan earthquake in Sichuan Province, a large number of buildings, water conservancy facilities, and transportation facilities were severely damaged. The damage caused by liquefaction and earthquake-induced soil subsidence was widely distributed, diverse, and extensive. Typical liquefaction and earthquake-induced subsidence damage for this region has been described by investigations of soils and foundations in the earthquake-stricken area. Factors that influenced the liquefaction of soils in Dujiangyan County were analyzed, accounting for regional geological conditions. The results identify several factors that may affect the process of liquefaction and general damage to buildings, roads, levees, and dams. Such factors could serve as the basis for further research into mitigating the damage caused by earthquake-induced liquefaction and subsidence. The importance of detailed ground reconnaissance and the implementation of reasonable and effective measures to improve soft soil are proposed for earthquake hazard reduction in similar areas.     

建（构）筑物的变形控制指标

城市轨道交通和其他市政地下工程建设难免造成周边建（构）筑物的变形,确定建（构）筑物的变形控制指标是进行安全监测和控制的基础。总结目前建（构）筑物控制的各类变形参数,对其定量化研究成果进行归纳,根据收集的大量变形监测资料,划分建（构）筑物的变形损坏等级,对其沉降、差异沉降和倾斜等常规监测项目进行重点分析,并研究了建筑尺寸和变形量、损坏等级的关系。研究结果表明,砂土地层独立柱基的建筑易于产生变形破坏,应防止建筑过量沉降引起的其他变形损坏;建（构）筑物的角变量小于0.002时一般未出现较大影响;建筑尺寸影响变形的大小,应密切关注易于出现变形损坏的多层、高层建筑。     

Application of fragility curves to estimate building damage and economic loss at a community scale: a case study of Seaside,Oregon

Community-scale estimates of building damage and economic loss are modeled for Seaside, Oregon, for Cascadia subduction zone events ranging from 8.7 to 9.3 M_W with corresponding slip distances of 3–25 m considering only the effects of the tsunami. Numerical simulations are obtained from the National Oceanic and Atmospheric Administration’s method of splitting tsunami model which includes a source model, subsidence, and calculations of the propagation and inundation flow characteristics. The damage estimates are based on fragility curves from the literature which relate flow depth with probability of damage for two different structural materials of buildings. Calculations are performed at the parcel level for the inundation hazard without including damage caused by the earthquake itself. Calculations show that the severity of building damage in Seaside is sensitive to the magnitude of the event or degree of slip because the majority of the city is located on low-lying coastal land within the estimated inundation zone. For the events modeled, the percentage of building within the inundation zone ranges from 9 to 88 %, with average direct economic losses ranging from $2 million to $1.2 billion.     

采空区上方修建大型建筑物地基稳定性评价

地表移动变形随时间的稳定性及剩余变形问题一直是采动覆岩沉陷研究的重要方面。笔者分析了采动地表移动变形的时间过程,探讨了地表沉陷的延续时间及地表剩余沉陷的预计方法,给出了采空区上方修建大型建筑物地基稳定性评价的指标,对采空区上建设建筑物提出了相应的技术措施。     

Landslide damage to buildings

Landslides are a significant and expensive hazard in urban areas, however, a universal methodology for classifying the damage to buildings has not been adopted This article proposes an intensity scale for structural damage caused by subsidence, compression, or extension of the ground during landslides and offers a checklist of site observations that could be made by planners, engineers, architects, surveyors, geologists, or gemorphologists.     

Structural damages of the May 19, 2011, Kütahya–Simav earthquake in Turkey

Reconnaissance observations are presented on the building damage caused by the May 19, 2011, Kütahya–Simav earthquake in Western Turkey as well as an overview of strong ground motion data recorded during the earthquake is given. According to Disaster and Emergency Management Presidency of Turkey, the magnitude of the earthquake is 5.7 in local magnitude scale. Although the earthquake can be regarded as a moderate event when considering its magnitude and strong motion recordings, it caused excessive structural damage to buildings in Simav district and several villages in the near vicinity. During the field investigation, different types of structural damage were observed mainly in the reinforced concrete frame buildings with infill walls and masonry buildings with various types of construction materials. Observed damage resulted from several deficiencies in structural and non-structural components of the buildings. Poor construction materials and workmanship, non-conforming earthquake-resistant design and construction techniques and non-ductile detailing are the main reasons for such an extensive damage, as observed in many past earthquakes in Turkey.     

Vulnerability to ground deformation phenomena in the city of Tuzla (BiH): a GIS and multicriteria approach

Ground deformation phenomena affecting the town of Tuzla (Bosnia Herzegovina), as consequence of underground salt deposits exploitation, have been surveyed since 60?years ago. The growing of cavities beneath the town and successive surface deformations have induced several hazard factors such as ground subsidence, deep and shallow fracturing and intense groundwater table oscillations. Fortunately, this processes had no catastrophic consequences such as sinkholes developing. Previous studies analyzed the historical database of topographic and piezometric data and highlighted a cumulative subsidence rate up to 12 meters over a period spanning from the 1956 to the 2003. Fractures arose as obvious result of ground deformation and caused damages and demolitions to thousands of buildings, with almost 15,000 people evacuated. Nowadays, in order to diminish the deformation processes, a strong reduction in brine withdrawal has been introduced by the local authorities. This caused an uplift of the water table which actually makes the spatial pattern of deformation more complex. In fact, in the most urbanized area, the sinking phenomena are now turning into uplift displacements. The presence of such a hazard required an urban vulnerability assessment able to support local authorities in the forthcoming planning procedure. The vulnerability assessment of urban elements over a wide area, potentially affected by deformation phenomena, has been accomplished by an integration between GIS solutions and a multicriteria approach based on ELECTRE-TRI methodology. The vulnerability procedure is able to define a discrete map where the 50?×?50?m width elementary cells report the most vulnerable parts of the town. In particular, the ELECTRE-TRI methodology is used to combine each vulnerable urban element with the others, expressed as vector data in a geographical dataset. The multicriteria approach is performed outside the GIS environment by the ELECTRE-TRI 2.0 package and requires a preliminary rasterization of the used dataset.     

Scour hole depth prediction around pile groups: review,comparison of existing methods,and proposition of a new approach

Flooding is the most costly natural hazard event worldwide and can severely impact communities, both through economic losses and social disruption. To predict and reduce the flood risk facing a community, a reliable model is needed to estimate the cost of repairing flood-damaged buildings. In this paper, we describe the development and assessment of two models for predicting direct economic losses for single-family residential buildings, based on the experience of the 2013 Boulder, Colorado riverine floods. The first model is based on regression analyses on empirical data from over 3000 residential building damage inspections conducted by the Federal Emergency Management Agency (FEMA). This model enables a probabilistic assessment of loss (in terms of FEMA grants paid to homeowners for post-flood repairs) as a function of key building and flood hazard parameters, considering uncertainties in structural properties, building contents, and damage characteristics at a given flood depth. The second model is an assembly-based prediction of loss considering unit prices for damaged building components to predict mean repair costs borne by the homeowner, which is based on typical Boulder construction practices and local construction and material costs. Comparison of the two proposed models illustrates benefits that arise from each of the two approaches, while also serving to validate both models. These models can be used as predictive tools in the future, in Boulder and other US communities, due to adaptability of the model for other context, and similarities in home characteristics across the country. The assembly-based model quantifies the difference between the FEMA grants and true losses, providing a quantification of out-of-pocket homeowner expenses.     

高层建筑物荷载与地下水开采叠加作用下的地面沉降特征

在地下水开采和高层建筑荷载叠加作用下,城市地面沉降分布愈加复杂.以天津塘沽地区为例,考虑到土体在固结沉降中的平衡条件、弹性本构条件、变形协调条件和水流连续条件,以比奥固结理论为基础,建立了高层建筑荷载和地下水开采叠加作用下三维地面沉降模型,采用有限元方法进行了数值计算.结果表明,高层建筑物的附加荷载作用在其建成后的3～...     

建筑物对浅埋隧道开挖地表沉降的影响

采用解析法研究穿越地表建筑物浅埋隧道开挖引起的地表沉降。由无建筑物时岩土体开挖引起的地表沉降公式及半无限平面在均布荷载下的相对沉陷,推导出了穿越地表建筑物浅埋隧道施工引起的地表沉降公式,并通过实例验证了此方法的可行性。采用上述方法研究了地表建筑物的重量及其与浅埋隧道位置关系对地表沉降的影响,研究结果表明：浅埋隧道开挖引起的地表沉降随建筑物重量的增大而增大;建筑物中心到隧道轴线的水平距离是对地表沉降的一个重要影响因素,超过一定范围时建筑物的存在对地表沉降的影响可以忽略不计。研究结果可为类似隧道工程提供一定参考。     

Experimental vulnerability curves for the residential buildings of Iran

Iran is one of the most seismically active countries of the world located on the Alpine-Himalayan earthquake belt. More than 180,000 people were killed due to earthquakes in Iran during the last five decades. Considering the fact that most Iranians live in masonry and non-engineered houses, having a comprehensive program for decreasing the vulnerability of society holds considerable importance. For this reason, loss estimation should be done before an earthquake strikes to prepare proper information for designing and selection of emergency plans and the retrofitting strategies prior to occurrence of earthquake. The loss estimation process consists of two principal steps of hazard analysis and vulnerability assessment. After identifying the earthquake hazard, the first step is to evaluate the vulnerability of residential buildings and lifelines and also the social and economic impacts of the earthquake scenarios. Among these, residential buildings have specific importance, because their destruction will disturb the daily life and result in casualties. Consequently, the vulnerability assessment of the buildings in Iran is important to identify the weak points in the built environment structure. The aim of this research is to prepare vulnerability curves for the residential buildings of Iran to provide a proper base for estimating probable damage features by future earthquakes. The estimation may contribute fundamentally for better seismic performance of Iranian societies. After a brief review of the vulnerability assessment methods in Iran and other countries, through the use of the European Macroseismic method, a model for evaluating the vulnerability of the Iranian buildings is proposed. This method allows the vulnerability assessment for numerous sets of buildings by defining the vulnerability curves for each building type based on the damage observations of previous earthquakes. For defining the vulnerability curves, a building typology classification is presented in this article, which is representative of Iranian building characteristics. The hazard is described in terms of the macroseismic intensity and the EMS-98 damage grades have been considered for classifying the physical damage to the buildings. The calculated vulnerability indexes and vulnerability curves show that for engineered houses there is not any notable difference between the vulnerability of Iranian and Risk-UE building types. For the non-engineered houses, the vulnerability index of brick and steel structures is less than the corresponding values of the other unreinforced masonry buildings of Iran. The vulnerability index of unreinforced and masonry buildings of Iran are larger than the values of the similar types in Risk-UE and so the Iranian buildings are more vulnerable in this regard.     

湖南省谭家山矿区开采地质灾害分析

煤矿开采所产生的地表沉降、开裂、塌陷等地质灾害,造成地表民房不同程度的损坏。为准确分析矿山开采对地表民房的损坏,从矿山开采造成地表沉降影响范围,矿山开采最大冒落高度与导水裂隙带高度,矿山开采引起地表最大水平移动值、最大曲率值、最大倾斜值等因素来研究分析。综合分析认为：引起地表民房损坏的主要原因一是地表民房正处在采动影响范围内;二是开采冒落带与裂隙带高度已经波及至地表,从而引起地表出现沉降与裂缝等现象,引发房屋开裂等损坏现象;三是煤矿采空区所产生的最大曲率值远远大于地表建筑允许变形值。该方法对研究煤矿开采造成地表民房损坏成因分析具有一定指导意义。