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1.
Assessment of rockfall hazard around Afyon Castle,Turkey 总被引：2，自引：0，他引：2
The Afyon Castle is a tourist destination and a historical site in the City of Afyon in Turkey. The Castle is located on a
steep hill, with a height of 226 m. In close proximity to the Castle there are settlements. The hill consists of trachitic
andesite. The rock contains columnar joints and flow layering. Owing to these discontinuities, blocks of varying sizes had
fallen down. The settlement areas near the Castle are now in danger because of the rockfall risk. In this study, rockfall
analysis was carried out along nine profiles of the hill. Fall-out distance, bounce height, kinetic energy and velocity of
the rocks along each profile were investigated. The results of the analyses were evaluated, and the areas delineated as susceptible
to rockfall risk are highlighted. Remedial measures including rock bolts and protective fences were suggested on the basis
of the field observations and the rockfall risk evaluation. 相似文献
2.
M. K. Ansari M. Ahmad Rajesh Singh T. N. Singh 《Journal of the Geological Society of India》2018,91(1):47-56
The Saptashrungi gad temple (SGT) situated on basaltic hills belongs to Deccan volcanic of Upper Cretaceous to Lower Eocene, is one among the 51 Shakti Peeths and most holy place for pilgrims. Rockfall is a major problem in the past and causing danger to the lives of the villagers settled at the toe of the SGT hill as well as the pilgrims who perform parikrama along the tracks. On the evening of 16 April 2011, an old woman died due to rockfall at SGT hill when she was performing parikrama, moreover, two persons got injured during the deliverance process of this old woman from the continuous rockfall activity. The problem of rockfall could be linked to rainfall, jointing, weathering, man-made or the compounding of all. In this research, the rockfall hazard analysis at SGT hill is assessed using both 2D and 3D rockfall programs along the two parikrama paths: Parikrama Path 1 (or the Badi Parikrama Path ‘BPP’), and Parikrama Path 2 (or the Chhoti Parikrama Path ‘CPP’). Also, the study area of the SGT hill has been divided into eight zones (Zone#01 to Zone#08), based on field observations, orientations of joint sets and hill slope faces and eighteen topographic profiles (AA' to RR') have been taken from these eight zones for rockfall analysis. A detailed topographic survey along with field investigation has been carried out along the temple for ascertaining the nature of rock, discontinuity orientations, and slope geometry. DEM has been generated using topographic profile in ArcGIS to facilitate the 3D rockfall analysis. Maximum rock block sizes are taken into the analysis and run-out distance, bounce height, kinetic energy and velocity of the basaltic blocks are evaluated separately. Based on the analyzed data, the rockfall hazard zone map has been prepared and site having potential rockfall risks have been identified. Finally, wire/net meshing has been proposed after removal of unstable blocks as a stabilization and protection measures.It is worth mentioning here that for the first time rockfall hazard assessment was made in such detail for a site. Suggestions made are implemented by the State Government for the protection of the temple as well as the life of pilgrims performing the parikrama from the rockfall. 相似文献
3.
Rock fall is a common natural hazard causing significant damage to infrastructure and loss of life and property. This paper describes selection of prevention method, construction processes and the results of a rockfall hazard assessment for the village of Sarica (Gürün region, Turkey) based on an engineering-geological model. The study area is located on the lower parts of an area with very steep cliffs and 40-500 slopes with fractured sedimentary and volcanic rocks. Detailed studies have been conducted in the region to prevent the risk of any rockfalls. Maps and charts are prepared including the rock blocks that are likely to fall and the related housing area under the risk. It was found that block sizes reached 3 m3. Rockfall analyses were performed along the selected profiles using the Rocfall V.5.0 software. Kinetic energy, bounce height, horizontal location of rock end-points and velocity of the rocks along each section were evaluated separately for each profile. This data was used to select design and construction of rockfall preventing system. In this study professional type rock fall barrier (catchment fence) was used. This method was chosen because it was cheaper, more practical and reliable than others. 相似文献
4.
The prediction of rockfall trajectories below a rock cliff is essential in susceptibility, hazard and risk maps, particularity
close to populated areas. The Monte da Lua hill area in Portugal, a tourist destination close to the historic city of Sintra
(UNESCO World Heritage), is a typical granite boulder chaos landscape where from time to time rockfalls occur, the last such
event having occurred on 29 January 2002. This area is therefore suitable to develop a rockfall study in order to provide
hazard and risk maps a basis for mitigation measures. A preliminary investigation of the area leads to the identification
of 188 potentially dangerous boulders. Detailed locations and geotechnical characteristics in terms of geometry, strength
and context were sampled for each boulder. Digital elevations at 1 × 1 m resolution, known rockfall trajectory and building
locations are provided in a GIS project for the study together with the spatial database of boulder characteristics. The modelling
approach was conducted in two steps: (1) discrimination of the boulders in terms of static and dynamic mobility behaviour
with multivariate analysis; (2) stochastic simulation of rockfall trajectories. The rockfall trajectory algorithm proposed
is straightforward and is only dependent on elevation data, initial location of boulders and a friction angle. Due to the
slope of the area, it assumes that rockfall is always of the rolling or sliding type. The friction angle was calibrated on
the basis of the rockfall travel distance recorded on 29 January 2002 and generates simulated “realistic” trajectories. A
smaller friction angle increases all simulated trajectories, leading to more “pessimistic” scenarios. The combined analysis
of trajectories and potential damage to buildings and discrimination in terms of static and dynamic behaviour provides a final
table in which all 188 sampled boulders are classified in one of the five risk grades. 相似文献
5.
四川南部城市群为成渝经济区区域规划中四大城市群之一,有望成为四川省第二大增长极。区内多为丘陵山地型城市,有限的发展空间迫使城市建设活动中频繁的削坡、回填,在获得发展空间的同时也引发了大量的环境工程地质问题。地震活动、红层风化,地质灾害是区内最主要的环境工程地质问题。通过分析前人研究成果结合收集资料分析得出：华（？）山断裂及荥经-马边-盐津断裂在区内均表现为强活动性,地震活动频繁。侏罗系-白垩系红层泥岩具有快速风化的特性,红层边坡具有剥落、崩塌、落石、表层溜塌、滑塌、浅层滑坡六大破坏方式。区内地质灾害频发,发育密度达7.81处/100km~2,地质灾害类型以滑坡、崩塌为主。 相似文献
6.
隧道仰坡落石冲击模型试验研究与机制探讨 总被引：1，自引：0，他引：1
以在建的成都－兰州（成兰）铁路某隧道出口仰坡为研究对象,研发了大型落石冲击边坡模型试验系统,该系统由模型试验台架、落石三维空间释放装置、高速摄影系统等组成,结构强度高并能满足试验过程的可视化需求。根据现场岩样实测物理力学参数,采用凡士林、硅油、水泥、细沙、重晶石粉、石膏以及滑石粉等原料,研制出现场千枚岩和砂岩的相似材料,并用于模拟边坡和落石。通过开展物理模型试验研究了近长方体落石初始滑移角度、形状、质量等3种因素对碰撞恢复系数这一落石运动轨迹模拟中关键参数的影响,同时在落石下落冲击的过程中,利用高速摄影仪和坐标卡尺记录落石完整的运动轨迹,后期通过视频处理软件分析落石与边坡碰撞前后的速度变化,根据公式计算出落石法向和切向的碰撞恢复系数。试验结果表明：随着初始滑移角度的增加,板状试件的法向、切向恢复系数分别呈减小和增大的趋势,且切向恢复系数变化更加明显;落石法向恢复系数随质量的增加呈明显减小的趋势,而切向恢复系数值变化不大;对于近长方体落石,立方体试件的法向和切向恢复系数大于厚板状试件,条形试件的两向恢复系数值受碰撞接触形态的影响,呈现两极化的趋势。最后,结合试验现象以及前人的研究成果对落石运动冲击机制进行了初步探讨。 相似文献
7.
Rockfalls are common in the steep and vertical slopes of the Campania carbonate massifs and ridges, and frequently represent
the main threat to the anthropogenic environment, potentially damaging urban areas, scattered houses, roads, etc. Despite
the generally limited volumes involved, the high velocity of movement (from few to tens of metres per second) poses rockfalls
among the most dangerous natural hazards to man. Evaluating the rockfall hazard is not an easy task, due to the high number
of involved factors, and particularly to the difficulty in determining the properties of the rock mass. In this paper, we
illustrate the assessment of the rockfall hazard along a small area of the Sorrento Peninsula (Campania region, southern Italy).
Choice of the site was determined by the presence of a road heavily frequented by vehicles. In the area, we have carried out
detailed field surveys and software simulations that allow generating simple rockfall hazard maps. Over twenty measurement
stations for geo-mechanical characterization of the rock mass have been distributed along a 400-m-long slope of Mount Vico
Alvano. Following the internationally established standards for the acquisition of rock mass parameters, the main kinematics
have been recognized, and the discontinuity families leading to the different failures identified. After carrying out field
experiments by artificially releasing a number of unstable blocks on the rock cliff, the rockfall trajectories along the slope
were modelled using 2-D and 3-D programs for rockfall analysis. The results were exploited to evaluate the rockfall hazard
along the threatened element at risk. 相似文献
8.
滚石灾害是山区常见的地质灾害类型,研究滚石的运动特征对地质灾害调查及危险性评估有着重要意义。通过对尼泊尔某项目滚石灾害后现场进行工程地质调查,分析其灾害成因机制,查明事故原因。调查结果表明:9 ·15灾害非人类活动的影响,属自然地质灾害,造成事故的主要原因为超高位岩体崩塌,而滚石的范围又超过前期预测的危险区。通过现场痕迹分析,推测出滚石的运动路径。根据调查出的撞击点位置、物质组成及几何特征,作者提出运用运动学原理还原滚石运动轨迹,并利用rocfall软件对超高位危岩体崩落后的运动轨迹进行随机模拟分析,推算出超高位危岩体崩落后能量大小的变化,为防护措施方案提供可靠的依据。张口式帘式网韧性强,防护能级高,对高陡边坡滚石灾害能起到很好的效果。本文可为类似高陡边坡的危岩治理防护提供参考。 相似文献
9.
In this paper, a study aimed to assess the rockfall hazard along a portion of the SS18 coastal road, located in the coastal area of Maratea (Basilicata Region, Southern Italy), is presented. The relevance of this study derives from the location of the study area, because the SS18 is a strategic roads in a touristic area, and, since the hazard assessment was performed in 2004 within a project financed by the Viability Regional Department of Autonomous National Company of Roads (ANAS), from the possibility to validate the results by using real rockfall events occurred after 2004. The procedure for assessing the rockfall hazard was composed of four sequential analyses: (i) geomechanical and kinematic characterization of rock mass, (ii) implementation of Romana’s (1985) Slope Mass Rating (SMR) method for identifying the potential boulder release areas (rockfall initiation areas), (iii) determination of rockfall trajectories by using a 3D numerical model (ROTOMAP), (iv) calculation and mapping of the hazard index by combining three factors, i.e., (a) lithological features of outcropping materials on rock faces, (b) kinematic compatibility defined by simulating the rockfall trajectories, and (c) spatial distribution of occurred rockfall events. Finally, the proposed methodology was validated by combining the distribution of the hazard levels along the road with the location on the SS18 of the rockfall events occurred from 2004 to 2014. 相似文献
10.
Vishal V. Siddique T. Purohit Rohan Phophliya Mohit K. Pradhan S. P. 《Natural Hazards》2017,85(1):487-503
A massive disaster occurred in June 2013 in Kedarnath, India, due to cloudburst and extremely heavy rain along the Chorabari glacier. The resulting flash floods further aggravated the instability of natural and hill cut slopes at different places on the downstream side. The village Rambara that existed in close proximity of Kedarnath was swept away under flow of debris and water. The immediate surrounding area, which housed over a hundred and fifty shops and hotels, was completely washed away leaving no trace of civilization. This calamity in Uttarakhand is considered as India’s worst natural disasters after the tsunami in December 2004. On the downstream of the affected areas lie other pilgrim destinations that witness innumerable footfalls every year. Investigation of the health of the slopes on the routes to these destinations is therefore very important to ensure minimal damage to humans and machinery. The Himalayan terrain is a tectonically active mountain belt, having a large number of unstable natural and road cut slopes. Such slopes with rugged topography lie in the high seismic vulnerability zone. Further, the instability is aggravated by natural and anthropogenic activities increasing at a rapid and uncontrollable rate. In the light of the Kedarnath tragedy, more advanced research is being conducted along the National Highways to monitor and prevent slope/structure failures. This study was conducted to evaluate the hazard potential along National Highway-58, near Saknidhar village of Devprayag district by analysing rockfall using hazard rating systems and numerical simulation. Rockfall hazard rating systems were applied to evaluate the conditions of the slopes and to identify the associated risks. Based on the field and laboratory analyses, the parameters required for numerical models were determined. The bounce height, roll-out distance, kinetic energy and speed of the detached blocks were determined by using a competent rockfall simulator. The results obtained were used to identify rockfall risk in the region. Optimization strategies were applied during investigation by modifying the slope angle, ditch width and ditch angle to assess the possibility of a hazard to occur in different scenarios. The simulation studies revealed that an increasing slope angle could significantly increase the kinetic energy of the rock blocks. However, an increase in the ditch angle and the ditch width reduces the energy of moving blocks. The maximum bounce height above the slope varied from 0.003 m to 0.8 m for 10-kg blocks, whereas the maximum velocity and the maximum kinetic energy under such circumstances were 7.882 m/s and 379.89 J, respectively. The barrier capacity was found to be 233.18 J for 10-kg falling blocks at a height of 10.02 m. From the optimization studies, it was found that the risk can be reduced by up to 13 % if the slope of 70° has a ditch angle of 15° while on a flat ditch, the maximum risk will be at an angle of 65°. If the ditch angle is increased, the vertical component of the falling blocks is more effective than that in case of a flat ditch. These optimization studies lay foundation for advanced research for mitigation of rockfall hazards in similar potential areas.
相似文献11.
13世纪时,温泉寺就因后山崩塌而被毁坏。1977年7月14日后山陡崖——鹤鹰岩发生崩塌,体积达3500m~3,毁坏北温泉公园附近的北碚水文站,并造成人员伤亡。近期后山陡崖变形在加剧,通过勘察,初步掌握了变形特点,本文重点讨论变形的力学机制,并建立极限平衡方程,为评价和预测崩塌灾害提供依据。 相似文献
12.
Rockfall susceptibility zoning at a large scale: From geomorphological inventory to preliminary land use planning 总被引：3，自引：0，他引：3
Rockfall, up to several hundreds of cubic meters, is a frequent and rapid landslide which menaces extensive areas in mountainous territories. Rockfall susceptibility zoning map at a large scale (1:5000–1:25 000) can be the first tool for land use planning in order to manage rockfall risk. A methodology allowing to analyze susceptibility in extensive areas with optimum cost/benefit relationship is needed. This work analyzes rockfall susceptibility in an extensive rocky mountain of the Principality of Andorra (Pyrenees Mountains), first on the rock slope and then on the exposed area located below. The rockfall record, obtained by means of geomorphological analysis, supplies the main data to analyze the susceptibility on the rock slope. An additional historical inventory verifies the accuracy of rockfall sizes recorded by means of the geomorphological analysis. According to the classification recommended by the Guidelines of Joint Technical Committee, the density of rockfall features on the rock slope assesses susceptibility in four levels. Subsequently, susceptibility on exposed areas has been analyzed by means of reach probability of rock blocks analysis using empirical models. Data acquired from thirteen recent events, from 1999 to 2004, have been used to verify the accuracy of the two empirical models mainly used (reach angle and shadow angle). Five reach probability limits (1, 0.5, 0.25, 0.01, and 0) establish boundaries between susceptibility levels. The resulting rockfall susceptibility zoning map allows: (a) to identify land areas and human elements exposed to rockfalls and, (b) to establish several exposition levels. This map can be a useful and cost-effective tool for administrations responsible to manage natural risk in order to guide urban grow in extensive areas or decide upon work programs based on in-depth analysis (hazard and risk). 相似文献
13.
Failure mechanism in an extremely slow rock slide at Bitchu-Matsuyama castle site (Japan) 总被引：1，自引：1，他引：1
One of the specific problems related to historical structures is the fact that they are prone to damage caused by even very
small deformations acting over a long period of time, such as creep or extremely small rock displacements. If any damage has
already occurred, the determination of the rock slope failure mechanism is one of the prerequisites for successful mitigation
technique selection. In this study a medieval castle in central Japan, suffering damage caused by deformation of the rock
mass in the subgrade of the castle, was investigated using a combination of field investigation, high-precision monitoring
and physical modeling experiments. Using these techniques an attempt to determine the failure mechanism of the rock slope
was made. Based on the field investigation a toe-slope failure seemed to be the main triggering factor activating the deformations
in the upper slope area, right below the defense walls of the castle. The displacement monitoring of the surface rock blocks
revealed a slumping failure with the backward rotational component prevailing over the sliding in the immediate vicinity of
the castle wall. This was in accordance with the expectations obtained from the structural analysis of the rock mass carried
out during the field investigation. The displacements obtained during the rock block monitoring, especially from the crack
gauges, were not sufficient for drawing a satisfactory conclusions about the failure mechanism of the blocks located in the
central part of the slope. Therefore, the failure mechanisms of rock blocks inferred from their displacements obtained from
the monitoring were correlated with the results of modeling experiments carried out on the scaled slope model. The physical
modeling revealed a possibility of toppling failure of rock blocks in the central area of the slope caused mainly by block
interlocking, which was supported by the data from surface tilt meters installed additionally in the field. Furthermore, the
possibility of the occurrence of forward and backward rock block rotations in the same sliding body at given conditions was
supported by the physical modeling experiments. 相似文献
14.
15.
我国多山,崩塌灾害频繁发生,相应的风险评价也得到了越来越多的关注。由于崩塌发生和运移过程的高度不确定性以及历史数据的不完备,往往很难进行相应的定量风险评价。四川罗家青杠岭的崩塌现场非常典型,而且现场资料较全、历史数据较多并且明确,是开展崩塌风险定量研究的很好实例。通过现场工程地质调查、测绘和统计分析,确定了历史崩塌的物源区、堆积区、最大运移距离、年发生概率以及坡体上的4块典型危岩体A-D。基于历史崩塌堆积区的块石统计特征以及物源区危岩体失稳启动位置的不确定性,利用二维Rockfall模拟软件对所在坡面的恢复系数及摩擦系数进行了反演。在此基础上,对危岩体A-D失稳后的运动特征进行了随机性数值模拟和统计分析,从而确定了崩塌的到达概率。基于崩塌发生概率、到达概率、承灾体时空分布概率和易损性的乘积,作者对罗家青杠岭崩塌进行了定量风险评价。评价结果表明,危岩体A和D的风险值处于不可接受的风险区间,块石B和C的风险值处于警告的风险区间,严重威胁着坡脚附近居民的生命财产安全,有必要采取相应的防灾减灾措施。 相似文献
16.
B. Matasci G. M. Stock M. Jaboyedoff D. Carrea B. D. Collins A. Guérin G. Matasci L. Ravanel 《Landslides》2018,15(5):859-878
Rockfalls strongly influence the evolution of steep rocky landscapes and represent a significant hazard in mountainous areas. Defining the most probable future rockfall source areas is of primary importance for both geomorphological investigations and hazard assessment. Thus, a need exists to understand which areas of a steep cliff are more likely to be affected by a rockfall. An important analytical gap exists between regional rockfall susceptibility studies and block-specific geomechanical calculations. Here we present methods for quantifying rockfall susceptibility at the cliff scale, which is suitable for sub-regional hazard assessment (hundreds to thousands of square meters). Our methods use three-dimensional point clouds acquired by terrestrial laser scanning to quantify the fracture patterns and compute failure mechanisms for planar, wedge, and toppling failures on vertical and overhanging rock walls. As a part of this work, we developed a rockfall susceptibility index for each type of failure mechanism according to the interaction between the discontinuities and the local cliff orientation. The susceptibility for slope parallel exfoliation-type failures, which are generally hard to identify, is partly captured by planar and toppling susceptibility indexes. We tested the methods for detecting the most susceptible rockfall source areas on two famously steep landscapes, Yosemite Valley (California, USA) and the Drus in the Mont-Blanc massif (France). Our rockfall susceptibility models show good correspondence with active rockfall sources. The methods offer new tools for investigating rockfall hazard and improving our understanding of rockfall processes. 相似文献
17.
GIS-based evaluation of rockfall risk along routes in Greece 总被引：1，自引：0，他引：1
Andreas A. Antoniou 《Environmental Earth Sciences》2013,70(5):2305-2318
This article presents a GIS-based system, designed to assist in the management of rockfall risk along Greek routes. The system was developed in two stages; the field data collection led to the implementation of a rockfall rating system with its fundamental parameters, while the data process concluded to a rockfall data base and a GIS-based interface. The fundamental parameters were derived from the rockfall hazard rating system developed by Pierson et al. at the Oregon State Highway Division and provide a coherent approach to decide the type and the cost of protection measures to be applied in an area affected by rockfalls and presents highest rockfall risk. The system presented in this paper as well as the original system comprises exponential scoring functions that represent the increased hazard and reflected in nine categories forming the classification. The method presented in this paper modified certain categories from the original system which were described qualitatively and may lead to quite subjective estimations. These categories are ditch effectiveness; climate and presence of water on slope as well as rockfall history. Moreover, the original category “Geologic characteristic” was changed to Structural and Discontinuities Index; an index that relates blockiness of rock mass and orientation of joints with their weathering condition and their roughness. This index follows the classification of weathering and joint’s roughness suggested by International Society of Rock Mechanics, while other modifications regarding the categories “decision sight distance” and “roadway width” were applied based on Greek standards. An application of this modified method to a 3 km road which connects Athinios port and Fira, the capital of Santorini island, Greece, a high traffic intensity road where rockfalls periodically cause traffic interruptions is presented. The method was applied in fifteen cross sections of slopes adjacent to the road and the analyses showed increased risk and the need for urgent remedial works. 相似文献
18.
A Review of Studies Dealing with Tree Rings and Rockfall Activity: The Role of Dendrogeomorphology in Natural Hazard Research 总被引：1，自引：0，他引：1
M. Stoffel 《Natural Hazards》2006,39(1):51-70
Over the last few years, rockfall research has increasingly focused on hazard assessment and risk analysis. Input data on
past rockfall activity were gathered from historical archives and lichenometric studies or were obtained through frequency–volume
statistics. However, historical records are generally scarce, and lichenometry may only yield data with relatively low resolutions.
On forested slopes, in contrast, tree-ring analyses may help, generally providing annual data on past rockfall activity over
long periods. It is the purpose of the present literature review to survey the current state of investigations dealing with
tree-ring sequences and rockfall activity, with emphasis on the extent to which dendrogeomorphology may contribute to rockfall
research. Firstly, a brief introduction describes how dendrogeomorphological methods can contribute to natural hazard research.
Secondly, an account is provided of the output of dendrogeomorphological studies investigating frequencies, volumes or spatial
distributions of past rockfall activity. The current and potential strengths of dendrogeomorphology are then presented before,
finally, the weaknesses of tree rings as natural archives of past rockfall activity are discussed and promising directions
for further studies outlined. 相似文献
19.
İnan Keskin 《Environmental Earth Sciences》2013,70(4):1619-1628
Disasters caused by events such as earthquake, flooding, rock falls, landslides are often encountered. However, generally, the reasons for the destructive and devastating effects of these nature events are that settlement locations were chosen without site investigation studies, or that available studies were inadequate. Such inadequacies in the field are related to inappropriate settlement location and the resulting damage caused by rock falls. This study evaluated rockfall risk in a settlement that developed in a similar manner. The study was carried out in Bo?aziçi village of Kemah (Erzincan/Turkey), which is located in a very important tectonic zone. The study site is located on the lower sections of an area with very steep cliffs and 50–75° slopes. This cliff, which is the source of rockfalls, has a slope dip of approximately 90°. The cliff comprises 25–30 m high, fractured and cracked basaltic volcanic mass. To determine block size in the study area, scanline survey measurements and block size measurements were performed on blocks that loosened and fell from the cliff face. It was found that block sizes reached 6 m3. Rockfall analyses were performed along the selected profiles using the Rockfall V.4.0 software. Kinetic energy, bounce height, horizontal location of rock end-points, and velocity of the rocks along each section were evaluated separately for each profile. This data were used to produce distribution maps for each profile and the settlement was evaluated in terms of rockfall risk. The results indicate that the study area was at risk of future rockfalls and that it would be appropriate to relocate one part of the settlement. 相似文献
20.
G. M. E. Kamh 《Environmental Geology》2005,48(2):238-254
Conway Castle is an immense historical structure, dating back to 1289 AC. It was built on highly dipping thickbeds of indurated shale (argillite) and sandstone. It is surrounded by Conway Bay, railway lines, and tall dense forests indicating high relative humidity and rainfall in this coastal area. The castle suffers from weathering noted as honeycomb, black crust, exfoliation, and discoloration with white salt efflorescence at some parts; these are diagnostic features for salt weathering as confirmed by the laboratory investigations using scanning electron microscopy, X-ray diffraction (XRD), point XRD, and hydrochemical analysis. The salt is found to be from three sources, namely, water spray from Conway Bay that is part of the Irish Sea, chemical alteration of the mortars carbonate content into sulfate salts by acid rain, and wet deposition of air pollutants on the surface of the stone. The cracks noted in the southwestern tower of this castle are a result of landslides in this area that resulted from three factors: (a) high dip angle of the indurated sandstone and shale thickbeds (about 60–65° to the south) under this castle, (b) undercutting of these beds in the dip direction by the surface water of Conway Bay, and (c) seismic waves generated by the trains passing close to this castle. All these factors result in land sliding even at a low rate; however, the net result is cracks in the tower close to these factors. 相似文献