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1.
Summary The theoretical model of the relationship between sub-surface and surface subsidence movements proposed earlier by the authors of this paper is briefly described and further tested against another case history example. Using this model, the magnitudes of the maximum subsidence, tilt and horizontal strain at sub-surface horizons between the ground surface and seam level are predicted in terms of the magnitudes of the corresponding components at the surface due to the extraction of subcritical panels with a wide range of width-depth ratios and the results presented in the form of nomographs and tables. These graphs and tables could be used to estimate the maximum subsidence, tilt and horizontal strain at any chosen sub-surface horizon associated with the extraction of a subcritical panel from the known corresponding maximum values at the surface.The proposed theoretical model can also be used to predict sub-surface subsidence components at any point within the zone influenced by the extraction of a panel from the corresponding surface subsidence components which may be obtained from field measurements or pre-calculated using any existing method of surface subsidence prediction. As an example, the profiles of surface and sub-surface subsidence at various horizons between the ground surface and the seam level resulting from the extraction of an assumed sub-critical longwall panel are predicted using the theoretical model together with the empirical method of surface subsidence prediction. The pattern of sub-surface subsidence movements in the strata overlying the panel is examined. 相似文献
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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。 相似文献
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A.R. Selby 《Geotechnical and Geological Engineering》1999,17(3-4):351-371
Tunnelling through soils results in ground loss, causing surface settlements and transverse movements. Where the tunnel drive passes below an existing structure, it is important to estimate the effects upon the structure. However, the free ground deformations should not simply be imposed upon a structure, because the structure contributes to stiffening of the ground. A computational soil-structure interaction analysis is required, to otain detailed stress–deformation response. First, linear finite element and Lagrangian finite difference methods are used to estimate ground movements due to a tunnel in free ground, and the results are compared with values based on empirical equations. The two linear methods and an additional hybrid FE method are then used to assess with soil-structure interaction; two cases of a typical short wall and a long wall lying across the route of tunnels of different depths. The results support the validity of the hybrid method which is used to estimate interactive ground settlements for comparison with a reported case of tunnelling below a building in central London. A more detailed case study is then undertaken to assess building damage caused by gross settlements during tunnelling in mixed soils, at a site in Workington, west Cumbria. A survey allowed estimation of free ground movements. Analysis by the hybrid method on the soils plus uncracked structures indicated intolerable horizontal stresses. Re-analysis with major cracks introduced into the structures resulted in close agreement between measured and computed settlements. 相似文献
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Jian-Xiu Wang Bo Feng Li-Sheng Hu Yi-Qun Tang Xue-xin Yan Han-mei Wang Jin-bao Liu 《Environmental Earth Sciences》2013,69(1):93-102
The restrictions of the geo-environment are often ignored in urban planning, thereby directly causing a variety of geological hazards, including large areas of land subsidence in soft soil area. Based on the control objective of land subsidence, the geo-environmental capacity of ground buildings (GECGB) is defined. The relationship between floor area ratio (FAR) and land subsidence in Shanghai, China is analyzed. The results illustrate that land subsidence increases as FAR increases, and that the engineering environmental effect of the high-rise building group is the main factor affecting land subsidence in Shanghai, China. Hayashi’s Quantification Theory type I is selected to evaluate the GECGB of four typical areas in Shanghai. The prediction model is established based on existing background materials and the GECGB expressed by allowable FAR of the four typical areas are calculated. The evaluation approach promoted in this paper can be applied in urban planning to control the land subsidence induced by dense high-rise buildings. 相似文献
5.
Application of a Generalised Influence Function Method for Subsidence Prediction in Multi-seam Longwall Extraction 总被引：1，自引：1，他引：0
The purpose of mining subsidence prediction is to produce a reliable assessment of ground movement arising from underground mineral extraction. The results of the prediction are used to assess the likelihood of the associated effects on surface structures. In most countries, the assessment of mining subsidence has become an essential part of mining plans, which must be approved by relevant government bodies and mining regulators. It is therefore important to develop a subsidence prediction method that is suitable for a particular country or mine field. Further to the recent development of a Generalised Influence Function Method (GIFM) for subsidence prediction at RMIT University, a case study in Hunter coalfield of in New South Wales, Australia is presented to illustrate the applicability of the GIFM approach for subsidence prediction in multi-seam longwall mining. A computer program is used to calculate subsidence, horizontal displacement and principle strains arising from the extraction of longwall panels. The observed subsidence across the longwall panels and the corresponding ground movements are compared to the model’s output and the results analysed. A discussion of the discrepancies between the GIFM models and the behaviour of complex geological strata is presented. The GIFM method is found to be a powerful tool when applied to complex extraction configurations and can produce useful output for mining subsidence assessments. Of particular importance is its ability to provide both tensile and compressive strain information over the whole affected areas which would otherwise not have been available for the assessment of damage potential to surface structures. 相似文献
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Effects of mining subsidence on masonry buildings in Zonguldak hard coal region in Turkey 总被引：5，自引：4，他引：1
Gallerias are the underground constructed results of mining. As these space in underground layers collapse, horizontal and vertical ground movements occur and movement which may reach the earth’s surface are known as mining subsidence. The result of underground displacement may cause surface ground movement which can be detrimental to masonry buildings especially in hard coal regions. Thorough familiarity with general and regional characteristics of an affected area can assist reduction of the effects. Zonguldak and the nearby settlement area, with a population of 300,000, constitute the centre of a hard coal basin where extensive mining has a history extending through 160 years. Mining constitutes the main economic activity in this region, and consequently influences every aspect of life. This study’s intent is to identify the effects of mining subsidence on masonry buildings in the mining area of Kozlu, Zonguldak, Turkey and illustrate them with selected images of damaged masonry buildings. Also included are satellite and mining galleria images. 相似文献
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当盾构隧道平行侧穿建筑物时,大多关注建筑物的横向沉降规律,对其纵向沉降关注较少。为此,针对盾构隧道平行侧穿建筑物引发的空间变形开展研究。首先,对天津地铁6号线平行侧穿四座结构形式相近的砖混建筑的实测数据进行分析,得到建筑物基本变形模式;基于工程实测并考虑土体的小应变硬化特性建立三维有限元数值分析模型,研究了盾构侧穿引发的建筑物纵向挠曲、土体变形与应力变化规律,并分析了不同建筑平面长宽比的影响。结果表明,盾构隧道平行侧穿将诱发平面长宽比较大的建筑出现"下凹式"挠曲变形,纵墙中部沉降最大可为其角点沉降的2倍,平行侧穿并不能简化为平面应变问题进行分析。建筑物修建和盾构开挖将导致隧道上方土体经历较为复杂的应力变化过程,并可划分为6个阶段。沿建筑纵向基础中部的土体与边缘土体相比,其首先经历更大的压缩变形(建筑施工导致),在盾构穿越后又产生了更大的卸荷变形。当建筑平面长宽比小于2时,盾构开挖导致的纵向挠曲变形将显著减小。 相似文献
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结合理论推导和对工程实测数据的整理分析,对天然场地和存在邻近建筑物时2种情况下的墙后地表沉降形态进行了对比分析,采用上海软土地区墙后地表沉降经验公式,对存在建筑物超载情况下的地表沉降曲线进行了良好的拟合,直观地表示出地表沉降槽的大小及形状、墙后最大沉降点的位置等。结果表明,邻近建筑物的存在能显著改变天然场地的地表沉降曲线形态,是否考虑建筑物存在的影响,将影响到对基坑及周边环境安全状态进行正确的评价和预测。 相似文献
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Underground coal mining activities in Kozlu Hard Coal Basin have reached a level affecting ground layers inside the mining seams and the surface just above the mining operations, causing movements in vicinity of the basin. The movements emerge as collapsing in vertical direction and as sliding, curling and bending in horizontal direction and are termed mining subsidence since they exhibit themselves in ground layers and on earth surfaces in mining environments. These mining-induced movements cause damages and destructions on structures inside and on the surface of mining grounds, and the dimensions of these damages depend upon quality of structures and magnitude of movements. In order to contribute toward a solution to these problems and to mitigate the effects arising during and after mining activities, one should identify and investigate damage prone movements and determine the movement–time relationship. Therefore, it is immensely important to observe, investigate, and measure these movements in regions where mining activities take place. This study focuses on the surface movement-related deformations on the engineering structures in the basin such as Kozlu Seaport and some part of the Zonguldak-Kozlu Road. For this reason, subsidence monitoring points were established on the engineering structures in the basin in a geodetic network concept, and three periods of precise leveling and static GPS observations were conducted. Analyzing these two types of geodetic observations, active and residual subsidence effects were determined for both Kozlu Seaport and the Road nearby. 相似文献
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The classical influence function method is widely used in mining subsidence prediction, but its use is typically limited to predicting the subsidence associated with horizontal stratiform underground mining when the ground surface is flat. By investigating the topography influence on subsidence under simplified mining conditions, this study attempts to improve the original influence function method to take topographic variations into account. New asymmetrical influence functions are used to simulate element subsidence. Integrating this asymmetrical approach into the influence function method increases the realism of subsidence computation when compared to the numerical simulation results. The maximum subsidence value and influence angle got from field data are introduced into the improved method, then two field subsidence cases are studied and acceptable comparison results are achieved. This improved method should serve as the foundation for future work. 相似文献
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城市中心密集建筑群使得地铁需长距离穿越既有建（构）筑物,导致地面管井施工作业条件越来越难,降水沉降控制要求也越来越严。从轨道交通工程建设出发,当受施工场地限制时,提出在导洞内施工管井,并对降水导洞的设计、成井机械及施工工法进行了论述。针对施工降水引起的附加沉降,采用地下水三维渗流与地面沉降耦合模型计算软件——Pro-cessing Modflow,建立地下水流场与地面沉降的耦合模型,根据现场监测数据,运用参数修正后的模型,设计不同的抽降方案,分时段进行沉降预测,及时分析施工降水对周围环境的影响程度,可指导类似工程施工,具有重要的工程实际意义。 相似文献
14.
Centrifuge modeling of land subsidence caused by the high-rise building group in the soft soil area 总被引：1，自引：1，他引：0
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. 相似文献
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通过经验、理论分析和数值模拟等预测方法,并结合实测数据研究分析土压盾构施工引起的地表沉降问题.分析结果表明:预测方法估算的最大沉降值总高于实测的沉降值;Oteo方法的曲线形态更优化;当隧道埋深较浅时,Loganathan-Poulos、Sagaseta、Peck和Verruijt-Booker方法均过高估算了最大沉降量,且Loganathan-Poulos、Sagaseta和Verruijt-Booker方法给出的沉降槽偏宽;数值模拟方法比分析和经验方法更有效,可以有效模拟施工过程.根据研究结果,经验、理论分析和数值模拟方法具有一定的安全储备空间,可用于软土地层中土压盾构施工引起的地面沉降预测. 相似文献
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Structures affected by mining subsidence are exposed to heavy damage potential in relation to the induced tensile or compressive horizontal ground strains. This study intends to specify and compare the mining subsidence effect in terms of building transmitted movements or induced stresses, given the soil–structure interaction phenomena produced at the interface between a “stiff” elastic structure and a “flexible” elastoplastic soil. 相似文献
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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. 相似文献
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Impact of local site conditions on portfolio earthquake loss estimation for different building types
Elnaz Peyghaleh Vahidreza Mahmoudabadi James R. Martin Alireza Shahjouei Qiushi Chen Mohammad Javanbarg Sara Khoshnevisan 《Natural Hazards》2018,94(1):121-150
This article presents a sensitivity analysis investigating the impact of using high-resolution site conditions databases in portfolio earthquake loss estimation. This article also estimates the effects of variability in the site condition databases on probabilistic earthquake loss ratios and their geographical pattern with respect to structural characteristics of different building types. To perform the earthquake loss estimation here, the OpenQuake software developed by Global Earthquake Model is implemented in Clemson University’s supercomputer. The probabilistic event-based risk analysis is employed considering several notional portfolios of different building types in the San Francisco area as the inventory exposure. This analysis produces the stochastic event sets worth for 10,000 years including almost 8000 synthetically simulated earthquakes. Then, the ground motion prediction equations are used to calculate the ground motion per event and incorporate the effect of five site conditions, on amplifying or de-amplifying the ground motions on notional building exposure locations. Notional buildings are used to account for various building characteristics in conformance with the building taxonomy represented in HAZUS software. The HAZUS damage functions are applied to model the vulnerability of various structural types of buildings. Finally, the 50-year average mean loss and probabilistic loss for multiple values for probability of exceedance (2, 10, 20, and 40%) in 50 years are calculated, and the impact of different site condition databases on portfolio loss ratios is investigated for different structural types and heights of buildings. The results show the aggregated and geographical variation of loss and loss ratio throughout the region for various site conditions. Comparing the aggregated loss and loss ratio, while considering different databases, represents normalized differences that are limited to 6% for all building taxonomy with various heights and for all PoEs. However, site-specific loss ratio errors are significantly greater and in some cases are more than 20%. 相似文献
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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。 相似文献