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1.
Groundwater bearing alluvial units in the seismically active settlement areas may bring out probable damage on the urban and
built environment due to liquefaction. Bolu settlement area and surroundings are located in the North Anatolian Fault Zone.
Geotechnical boreholes were drilled in order to determine the distribution of the geological units, to obtain representative
soil samples and to measure groundwater level. Quaternary aged alluvium is the main geological unit in the South of study
area. Stiffness and consistency of the soils were determined by Standart penetration test. P and S wave velocities of soil
have been measured along the seismic profiles. The index and physical properties of the samples have also been tested in the
laboratory. Liquefaction potential and safety factor of the sandy levels in Quaternary aged alluvium were investigated by
different methods based on SPT and V
s. Liquefaction seems to be a significant risk in case of an earthquake with a
max = 0.48 g and M
w
= 7.5 at different levels of the boreholes. This situation may bring out environmental problems in the future. 相似文献
2.
陕西泾阳南塬黄土滑坡灾害与引水灌溉的关系 总被引：18，自引：0，他引：18
陕西泾阳南塬塬边黄土滑坡频繁发生，造成的经济损失和人员伤亡极为惨重。本文讨论了区内黄土滑坡灾害形成的地貌地形及地质环境特征，着重分析了人类不合理的引用地表水灌溉，改变了地下水文条件，从而降低了土体的抗剪强度，导致黄土滑坡形成的过程和机制。通过研究认为，合理进行灌溉，控制地下水位是改善塬边地质环境和防治滑坡灾害的关键措施。 相似文献
3.
Yao Jiaming Lan Hengxing Li Langping Cao Yiming Wu Yuming Zhang Yixing Zhou Chaodong 《Landslides》2022,19(3):703-718
The Sichuan-Tibet railway goes across the Upper Jinsha River, along which a large number of large historical landslides have occurred and dammed the river. Therefore, it is of great significance to investigate large potential landslides along the Jinsha River. In this paper, we inspect the deformation characteristics of a rapid landsliding area along the Jinsha River by using multi-temporal remote sensing, and analyzed its future development and risk to the Sichuan-Tibet railway. Surface deformations and damage features between January 2016 and October 2020 were obtained using multi-temporal InSAR and multi-temporal correlations of optical images, respectively. Deformation and failure signs obtained from the field investigation were highly consistent. Results showed that cumulative deformation of the landsliding area is more than 50 cm, and the landsliding area is undergoing an accelerated deformation stage. The external rainfall condition, water level, and water flow rate are important factors controlling the deformation. The increase of rainfall, the rise of water level, and faster flow rate will accelerate the deformation of slope. The geological conditions of the slope itself affect the deformation of landslide. Due to the enrichment of gently dipping gneiss and groundwater, the slope is more likely to slide along the slope. The Jinsha River continuously scours the concave bank of the slope, causing local collapses and forming local free surfaces. Numerical simulation results show that once the landsliding area fails, the landslide body may form a 4-km-long dammed lake, and the water level could rise about 200 m; the historic data shows that landslide dam may burst in 2–8 days after sliding. Therefore, strategies of landslide hazard mitigation in the study area should be particularly made for the coming rainy seasons to mitigate risks from the landsliding area.
相似文献4.
Assessment of a coastal landslide subjected to building loads at Sinop, Black Sea region, Turkey, and stabilization measures 总被引：1，自引：0，他引：1
《Engineering Geology》2004,75(1):69-88
The large landslides along the Black Sea shore in Turkey are well-known instability phenomena and responsible for considerable economic losses each year. The severity of the problem increased particularly in recent years as increased scarcity of land forced utilization of inherently unstable areas. In 1988, severe rainstorms at the city of Sinop on the Black Sea shore triggered ground movements on a gentle coastal slope subjected to building loads and caused extensive damage to buildings founded on the slope. Comprehensive investigations of the failure were carried out and used to establish a geotechnical model for the slide. The model allowed consideration of building loads and different groundwater conditions. In addition, the model studies were complimented by limit-equilibrium and finite-element stress analyses. The results indicated movements on a circular sliding surface through stiff clay. The toe of the landslide is located at the shoreline and remains active. The failure was probably initiated by rising groundwater level combined with surcharge loads imposed by buildings on the slope. Other contributing factors include sand extraction and coastal erosion. Remedial works are recommended involving a rockfill buttress at the toe of the slide and drainage improvements on the surface of the slope. 相似文献
5.
Vuthy Monyrath Yasuo Sakura Akinobu Miyakoshi Takeshi Hayashi 《Environmental Earth Sciences》2010,60(5):923-932
Previous studies and borehole temperature measurements suggest that subsurface temperature distribution on the west side of
Tokyo Bay (from Tokyo to Yokohama) is higher than that of the east side (Chiba side). To understand the groundwater flow and
other factors which may contribute to the subsurface temperature discrepancy such as geological setting in the study area,
groundwater temperature profiles were measured in 119 boreholes around the Tokyo Bay from 2002 to 2007. The data were analyzed
and compared with previous studies. Horizontal distribution of subsurface temperature at the depths of −50 and −100 m was
made to show the distribution of thermal regime. A cross-section across the bay of Tokyo was made to see the isothermal lines
and distribution of hydraulic heads in a vertical perspective. These results show that the highest subsurface temperature
zone is in the Tokyo area, along the river valley. Subsurface temperature at the depth of 50- and 100-m below sea level in
the western part of the bay is comparatively higher than its eastern side at the same elevation and distance from the bay.
This fact suggests that there is a regional groundwater flow system in the area and it is strongly affected by the geological
structure, particularly buried valley systems of the bay during the Paleo-Tokyo River and the topographical driving force
which is the result of the different elevation of recharge areas. Groundwater discharge is concentrated along the buried valley of Paleo-Tokyo River. 相似文献
6.
Process of slip-surface development and formation of slip-surface clay in landslides in Tertiary volcanic rocks, Japan 总被引：10，自引：0，他引：10
Once landslide movement has been initiated, the sliding mass tends to move toward a more stable position. However, landslides that have occurred in some Tertiary volcanic rocks in Japan show recurrent movement. A possible reason for this behavior is that the mineral composition and properties of slip-surface materials results in better ‘lubrication’ along the slip surface as movement continues. In order to determine the causes, five landslides in Japanese Tertiary volcanics with different movement histories were studied. Based on geological investigation, the results presented in this paper were obtained by studying the development process and formation of slip surfaces and clays in landslides in these volcanics.
For rocks of similar types and mineralogies the clay content of slip-surface materials can be directly related to the displacement and history of slide movement. This study indicates that the type of slip surface ranges from: (1) striation type (showing only striations on bedrock without clay), to (2) brecciated type (clayey breccia), (3) mylonite type (clay with breccia), and to (4) clay type (clay without breccia). If the slip surface occurs in tuff or tuffaceous materials and is subjected to increasing slide movement, the smectite content in the slip-surface clay increases, while the silicate mineral content decreases. Furthermore, the smectite content is observed to increase within the same landslide from the head to the toe portion of the landslide (direction of groundwater flow). The groundwater along the slip surface (above the impervious zone) contains an increased concentration of Ca++ ions. As the concentration of HCO3− ions exceeds 40 mg/l, an environment is created that promotes the formation of smectite. This process indicates that there is an active ion exchange within the groundwater near the slip surface that forms smectite. Thus, the formation of smectite in the slip surface requires the presence of tuff and a sufficient concentration of HCO3− ions in the groundwater.
The study results presented here indicate that frictional resistance decreases as clay content increases. The reason for repeated movement of Japanese landslides in Tertiary tuffs or tuffaceous rocks at or in the immediate vicinity of the slip surface is attributed to: (1) an increase in clay materials along the slip surface as the slide movement is repeated and (2) the presence of groundwater that promotes the formation of smectite. As is commonly known, smectite is one of the clay minerals that has lowest frictional resistance. 相似文献
7.
Landslides in Sado Island of Japan: Part I. Case studies, monitoring techniques and environmental considerations 总被引：1，自引：0，他引：1
Lulseged Ayalew Hiromitsu Yamagishi Hideaki Marui Takami Kanno 《Engineering Geology》2005,81(4):419-431
A sufficient knowledge on the kinematics and development of landslides helps to adopt proper measures that can be used to protect slopes and the environment in general. This can be achieved by adequate monitoring programs. This paper presents the findings of intensive monitoring activities carried out on Shiidomari and Katanoo landslides found in Sado Island of Japan. More than one year of observation of the two landslides allowed defining some peculiar futures of their kinematics and style of development. The problem of slope instability in the two areas is generally accredited to various factors. But, both landslides were triggered by heavy rainfalls and snowmelt. Because of the outline of the area and the presence of relict topographic features, the Shiidomari landslide is considered to be a large-scale reactivation of old slope failures. The Katanoo landslide is, however, a first-time case. Geophysical investigations and drilling activities in Shiidomari indicated the presence of two slip planes. The deepest (80–100 m) of these is controlled by existing lineaments. Monitoring data suggests that the body of the landslide has subsided as much as 1.16 m just below the main scarp, but a centimeter in the central region. The toe sector also experienced a significant amount of subsidence, but this was counter-balanced by an uplift on the opposite side of the landslide. Hence, the landslide seems not any more active along the deepest slip surface, although it may extend upward and define a series of shallow shear planes around the crown. In the case of Katanoo, the landform characteristics, differential weathering, the road cut and groundwater fluctuations appeared to contribute much to determine the exact location of the landslide. Extensional cracks that preceded the landslide can be related to heavy rainfalls and the cold and warm cycles thereafter. Subsurface investigations and monitoring works indicated that the landslide has two slide blocks with different slip planes. During the observation period, the upper part of the landslide responded more effectively to rainfall and snowmelt than the middle and lower sections. The corresponding movements, however, appeared to settle about three months after failure. There were also little strain transmissions in boreholes and no significant change in the characteristics of the landslide. The kinematics of deformation of many of the slopes in Sado Island resembles that of Shiidomari landslide. But mass movements along highways and mountain roads are usually similar to Katanoo. Landslides of the type like Shiidomari may not show sudden and drastic failures, but are usually long lasting and can reactivate repeatedly along new, shallow shear planes. Monitoring works and long-term supervisions in these types of landslides are useful to identify impending failures and take the right measures before they brought about large-scale destruction to the environment. 相似文献
8.
The Dead Sea is a terminal lake whose level is currently dropping at a rate of about 1 m per year due to the over exploitation
of all its tributaries. The lowering started about four decades ago but geological hazards appeared more and more frequently
from the end of the 1980s. The water level lowering is matched by a parallel groundwater level drop, which results in an increasing
intensity of underground and surface water flow. The diagonal interface between the Dead Sea brine and the fresh groundwater
is pushed downwards and seawards. Nowadays, sinkholes, subsidence, landslides and reactivated salt-karsts affect wide coastal
segments. Until now, mainly infrastructures were damaged and few people/animals were injured, but the ongoing development
of tourism in this very attractive situation will increase the risk if precautionary measures are not included in the development
plans. This paper discusses the main observations made all around the Dead Sea and shed a light on the differences between
the geological hazards of the western shore (Israel, Palestinian Authority) and the eastern shore (Jordan). It is the first
attempt to bring together an overview of the human-induced geological hazards encountered along the Dead Sea coast. 相似文献
9.
Confined groundwater near the rockhead in igneous rocks in the Mid-Levels area, Hong Kong, China 总被引：1，自引：0，他引：1
It is customary in Hong Kong to assume that the hydraulic conductivity of weathered igneous rocks decreases with depth or as the rock mass becomes less weathered. Such a hydraulic conductivity pattern can only lead to an unconfined aquifer. This paper presents a case study in the regions in and around the Mid-Levels area in Hong Kong regarding a possible relatively high hydraulic conductivity (K) zone and confined groundwater along the rockhead. The Mid-Levels area is located at the lower part of the north-facing slopes of Victoria Peak on Hong Kong Island and is prone to landslides. Although this site has a long history of geotechnical studies because of extensive urban development along the coast and public concern on slope stability, hydrogeology of the site remains poorly understood. This paper reexamined the hydraulic conductivity data in 7 boreholes conducted in the 1970s and found that 4 of them indicate an increase in K at the rockhead. Groundwater conditions revealed by tunnel construction at the coast suggest that K close to the rockhead is about 10 times greater than above rockhead. A careful analysis of storm response of a piezometer group with tips in different depths indicates that there was an upward flow from the bedrock to the colluvium. A field study of two overflow standpipes conducted by the authors showed that the water level can be 0.64 and 3.73 m above the ground surface, which illustrates that the deep groundwater is significantly artesian. A search of the archived site investigation reports from the government and private companies has led to an identification of about 24 sites with overflow boreholes, which suggests that overflow phenomenon is quite common in the study area. The paper then concludes that in the study area there is a relatively high K zone along the rockhead and the groundwater in the zone is confined. It is recommended that geotechnical engineers should carry out a more careful field study on an overflow borehole because such a borehole indicates a confined groundwater condition important for slope stability study and foundation design. 相似文献
10.
Cheng-Chao Lee Louis Loung-Yie Tsai Chieh-Hou Yang Kuo-Liang Wen Zi-Bin Wang Zhi-Hsian Hsieh Hsing-Chang Liu 《Environmental Geology》2009,58(7):1397-1406
A slope on the west border of the foothill near 921 surface rupture (caused by the 1999 Chi-Chi earthquake) in central Taiwan
shows distinctive topographic expression that was prone to be considered as a fault scarp formed by a preexisting active fault.
The 2D and 3D resistivity images clearly delineate rock surfaces which show steep, deep, gentle, and subvertical displacement
beneath the slope, the toe of slope, the non-lateritic terrace, and 921 surface rupture, respectively, which can be attributed
to the significant contrast of resistivity between gravel and rock. The horizontal sand bed and clast-supported gravel were
deposited in a fluvial environment, whereas wedge-shaped gravel and colluvium were scarp-induced colluvial deposits in the
trench profile. The layers shown in the depth of excavation, except for rock, has no offset or disturbance by fault ever since
at least 2,480 ± 50 year B.P., based on carbon 14 dating of charcoal sample at the bottom of trench profile. According to
information from two boreholes close to the slope, an over 20-m-thick marker bed with transported shell fragments, was found
for correlation. This correlation further implies the slope was not formed by fault. On the other hand, two boreholes which
are far from the slope and located on the flat non-lateritic terrace frequently show fractured and sheared features. By comparison,
the locations around these two boreholes indicate a reverse fault or faults that occurred before the deposition of gravel.
Later on, the paleostream was developed along the foot of fault scarp that was subjected to erosion and led to subsequent
retrogression or retreat of the slope. Consequently, the incision of paleostream is believed to be responsible for the high
relief of rock surface around the slope. Furthermore, from resistivity and borehole data, the rock surface underlying terrace
is gentle where no faults occur after the deposition of gravel. The result of RIP crossing the 921 surface rupture displays
about 10 m difference in elevation of rock surface on both sides, which is greater than that of 3–4 m caused by Chi-Chi earthquake.
This indicates that the 921 surface rupture is a preexisting thrust fault that resulted from several thrusting events since
terrace gravel was deposited. So it is not necessary to establish an extra restricted zone for construction in study area,
except close to the 921 surface rupture. 相似文献
11.
In the periods 1980–1986 and 1990–2007 many boreholes were sunk during hydrogeological investigations in the center of the
Karlovy Vary (Carlsbad) hot spring system. The extent and the depths reached were the greatest in the history of the geological
investigation of the discharge area of the thermal system. The results of the drilling program enabled a detailed study of
the rocks, groundwater and spring sedimentation in the area as well as the preparation of new proposals for changes in the
spring-protection zones. The spring sedimentation consists of world-renowned hot spring travertine, with a wide range of morphological
varieties of different origins and of different ages. The oldest U-series age data (230 ± 14 ka BP) have been obtained for
travertine relicts located 22 m above the present-day bottom of the narrow valley of the Teplá River. Five other travertine
deposits, partly overlapping in space and time were identified on the bottom and slopes of the valley. They were formed by
gradual growth, by river erosion and since the fourteenth century by human activities. 相似文献
12.
13.
14.
On July 22, 2013, an earthquake of Ms. 6.6 occurred at the junction area of Minxian and Zhangxian counties, Gansu Province, China. This earthquake triggered many landslides of various types, dominated by small-scale soil falls, slides, and topples on loess scarps. There were also a few deep-seated landslides, large-scale soil avalanches, and fissure-developing slopes. In this paper, an inventory of landslides triggered by this event is prepared based on field investigations and visual interpretation of high-resolution satellite images. The spatial distribution of the landslides is then analyzed. The inventory indicates that at least 2330 landslides were triggered by the earthquake. A correlation statistics of the landslides with topographic, geologic, and earthquake factors is performed based on the GIS platform. The results show that the largest number of landslides and the highest landslide density are at 2400 m–2600 m of absolute elevation, and 200 m–300 m of relative elevation, respectively. The landslide density does not always increase with slope gradient as previously suggested. The slopes most prone to landslides are in S, SW, W, and NW directions. Concave slopes register higher landslide density and larger number of landslides than convex slopes. The largest number of landslides occurs on topographic position with middle slopes, whereas the highest landslide density corresponds to valleys and lower slopes. The underlying bedrocks consisting of conglomerate and sandstone of Lower Paleogene (Eb) register both the largest number and area of landslides and the highest landslide number and area density values. Correlations of landslide number and landslide density with perpendicular- and along-strike distance from the epicenter show an obvious spatial intensifying character of the co-seismic landslides. The spatial pattern of the co-seismic landslides is strongly controlled by a branch of the Lintan-Dangchang fault, which indicates the effect of seismogenic fault on co-seismic landslides. In addition, the area affected by landslides related to the earthquake is compared to the relationship of “area affected by landslides vs. earthquake magnitude” constructed based on earthquakes worldwide, and it is shown that the area affected by landslides triggered by the Minxian–Zhangxian earthquake is larger than that of almost all other events with similar magnitudes. 相似文献
15.
Thomas Strauhal Simon Loew Michael Holzmann Christian Zangerl 《Hydrogeology Journal》2016,24(2):349-371
The hydrogeology of the deep-seated, slowly creeping Klasgarten rockslide in Austria is investigated in this study based on detailed surface and subsurface field data, laboratory analyses, and analytical and numerical simulations. Field data are derived from several deep exploration and monitoring boreholes, an exploration drift located within the rockslide, and geological and geomorphological mapping. Particular attention is given to the pore pressure measurements and their temporal and spatial variability. These pore pressure variations are controlled by a thin layer of clayey fault gouge (representing the basal shear zone of the rockslide), a high-permeability rockslide mass, and moderately fractured paragneissic bedrock. Variably saturated equivalent-continuum hydraulic conductivities and storage properties are derived from packer tests, laboratory tests and optical televiewer images. These data sets are used for two-dimensional numerical groundwater models to study the flow-field and pore-pressure variations caused by the reservoir water-level fluctuations, the transient groundwater infiltration from snowmelt and precipitation along the slope, and the exploration drift. The strongest pressure transients in the rockslide are caused by reservoir level fluctuations and not the natural groundwater recharge, even at substantial distances from the reservoir. The response times are very short and only a minor distance-dependent attenuation is observed. The results of this study are essential to analyse the hydromechanical control of the deformation behaviour of rockslides adjacent to hydropower reservoirs. Further, it helps to understand how the formation of a rockslide can change the original bedrock aquifer. 相似文献
16.
Various fracture filling minerals and secondary minerals in fracture walls were formed by fluid-rock interaction during the exhumation of the Palaeogene Shimanto Belt of Kyushu, Japan, which is located in an accretionary complex. Each mineral formed under favourable geological conditions and can be used to estimate the conditions of accretion and formation of the related rock sequences. Petrographic observations, mineralogical and geochemical analyses were made on fracture filling minerals and secondary minerals from boreholes of ca. 140 m depth, drilled in the Shimanto Belt. Results reveal that the secondary minerals were formed in three major stages distinguished by the sequential textural relationships of the minerals and the interpreted environment of mineral formation. Filling mineral assemblages show that the studied rock formation has been subducted to a depth of several km and the temperature reached was ca. 200–300 °C. After the subduction, the rock formation was uplifted and surface acidic water penetrated up to 80 m beneath the present ground surface. The acid water dissolved calcite fracture filling minerals to form the present groundwater flow-paths, which allowed recent wall rock alteration to occur. The results shown here imply that filling mineral assemblages can be an effective tool to evaluate the environmental changes during exhumation of an accretionary complex. 相似文献
17.
南阳膨胀土渠道滑坡破坏特征与演化机制研究 总被引：3，自引：0，他引：3
为了解河南南阳地区膨胀土渠道边坡滑坡机制,基于南水北调中线工程南阳段19个滑坡的现场调研统计结果,选取南阳段TS105+400处右岸滑坡为典型实例,开挖探槽揭露滑坡内部结构,对该区膨胀土渠道滑坡的破坏特征及演化机制进行了研究。结果显示,该区滑坡多发生在 地层;边坡的稳定性受中上部土体中的垂直节理及坡脚充填强膨胀土的缓倾长大裂隙共同控制,滑动面由后缘陡倾裂隙及前缘缓倾长大裂隙组成。开挖卸荷导致垂直节理张开,垂直节理向下可延伸3 m以上,破坏边坡土体整体性,且充当水分出入边坡的主要通道;坡面以下深度4～8 m存在一个高湿度带,带内土体强度小,发育滑动面。气候造成的胀缩循环、开挖卸荷导致边坡垂直节理张开并向深部发展,对边坡土体的强度衰减作用明显,当垂直裂隙与前缘缓倾裂隙贯通后,发生强（久）降雨,裂隙充水软化,即诱发边坡失稳。 相似文献
18.
滑坡分类研究一直是滑坡研究的基础和重点。通过对山西煤矿区滑坡灾害的工程实践和大量的调查统计分析,根据滑坡地层结构、岩性特征、诱发机制及运动特征等因素将山西煤矿区滑坡归结为5种类型:顺基岩面推移-滑动型黄土滑坡;蠕滑-挤出型黄土滑坡;水浸溜滑型黄土滑坡;煤层自燃倾覆-拉裂滑移型岩质滑坡;受节理控制的蠕滑-张裂型岩质滑坡。研究结果发现:黄土滑坡滑带土一般为松散土层,岩质滑坡的滑面为软弱结构面（多为泥岩薄层）或煤线;除溜滑型黄土滑坡滑动速度较快外,其他为低速滑坡,其典型特点是历时长,滑距短,致灾范围小,但滑坡推力大,破坏力强,往往造成更大损失。该研究进一步细化了滑坡分类的内容,其成果可对山西矿区及类似滑坡地质灾害的防治提供指导。 相似文献
19.
Hydrogeological and geotechnical assessments of the Kadifekale landslide area, İzmir, Turkey 总被引：1，自引：0，他引：1
The study area is located in the south of İzmir city centre in an area built without planning permission or any overall city
plan. In this area, a number of mass movements occurred in the past and the region is still an active landslide field at present.
The real sliding factor is geological structure, which is made up of hard volcanic rocks overlying soft Neogene clayey soils,
and forms a typical structure prone to sliding. Unplanned human activities change the hydrogeological and geotechnical stabilities
of the geological formations in a negative way. Rain and water leaking either directly from the mains or septic holes infiltrate
into the ground and act as one of the factors in causing landslides. It is clearly shown that the irregular urbanization in
and around Kadifekale is one of the factors contributing to the landslides in the area. To prevent the occurrence of landslides
in the study area an effective surface and under ground drainage should be established. Rain and wastewater should be removed
from the area by separate systems. Slopes should be reduced, water-loving trees should be planted and construction of high
rise buildings should be avoided.
Received: 12 December 1997 · Accepted: 4 April 2000 相似文献
20.
This paper presents the combination of two complementary methods, magnetic and joint inversion of resistivity/TEM data, as
an effective approach to characterize groundwater reservoirs. Twenty stations of transient electromagnetic (TEM) and vertical
electrical soundings (VES) were measured and interpreted using a joint inversion technique to evaluate the subsurface low
resistivity zones connected to the groundwater reservoir. A complementary survey including 871 land magnetic stations was
carried out at the same area to detect the upper surface of the basaltic sheet, which represents the bottom of the Miocene
aquifer in the study area. The geological log from one borehole drilled in the zone was used to partially calibrate the calculated
models. The results revealed that the study area consists of five different geological units with ages ranging from Paleogene
(Oligocene) to Quaternary. The methodology provides good results at a very low cost when compared with drilling boreholes. 相似文献