考虑非饱和土基质吸力的丁家坡滑坡变形机制及稳定性评价

丁家坡滑坡位于云阳县黄石镇中湾村,对拟建的云阳—开州（云开）高速公路安全具有潜在的威胁。为了查明丁家坡滑坡特征,开展了野外工程地质测绘、钻探与试验测试,采用Geo-studio完全耦合计算模式分析了不同降雨工况下滑坡渗流场、应力场、位移场的变化,考察了基质吸力在滑坡稳定性评价中的作用,并计算了不同降雨历时、降雨强度下滑坡的稳定性系数。结果表明：（1）丁家坡滑坡的斜坡地形、松散的岩性、潜在的临空面等因素决定了滑坡的形成与发育,坡体渗透性较好,降雨作用激励滑坡的变形,目前该滑坡处于蠕滑阶段;（2）降雨入渗后,坡体孔隙水压力增加,基质吸力减小,有效应力和抗剪强度降低,在土-岩界面形成剪应力集中,产生应变和位移,滑坡变形破坏;（3）高强度短历时的降雨使坡体浅层迅速饱和,易形成浅层滑,低强度长历时的降雨使坡体浸润较深,易造成深部滑动,其潜在滑动面主要为土-岩界面;（4）在非饱和状态下土体基质吸力对滑坡的稳定性具有重要影响;（5）目前滑坡处于基本稳定状态,一旦发生降雨,滑坡稳定性将降低,降雨历时越久、降雨强度越大,滑坡越易失稳。相对于滑坡Ⅱ区,滑坡Ⅰ区对云开高速公路安全的影响更大,应该重点对滑坡Ⅰ...     

东南沿海残积土地区降雨诱发型滑坡预报雨强-历时曲线的影响因素分析

东南沿海山地丘陵地区每年雨季期间有大量土质滑坡发生,如何对由降雨诱发的滑坡进行预报一直都是一个热点研究课题,雨强-历时曲线（简称I-D曲线）是目前国内外常用的降雨型滑坡预报的降雨量临界值曲线。针对东南沿海地区的浅层残积土滑坡,根据相关勘察数据及资料,概化得到了该类型边坡的地质剖面及岩土层性质,然后应用Geo-Studio软件分析了边坡初始湿润条件、土体抗剪强度、饱和渗透系数、边坡坡角、残坡积土层厚度及雨型等参数对I-D曲线的影响规律。分析结果表明：残坡积土抗剪强度参数、饱和渗透系数、边坡坡角、雨型等因素对I-D曲线的影响显著,边坡安全系数降至临界值所需降雨历时随抗剪强度参数值降低、表层残积土渗透系数增加或坡角增大而减少;当雨强较小时,初始湿润条件对I-D曲线的影响显著;当雨强大于残坡积土层饱和渗透系数时,入渗量主要由渗透系数控制,边坡安全系数降至临界值所需降雨历时不随雨强增大而变化。该研究结果为I-D曲线在东南沿海残积土地区降雨诱发滑坡预警预报中的应用奠定了基础。     

东南沿海台风暴雨型单体斜坡灾害风险评价——以泰顺仕阳北坡为例

在东南沿海地区每年汛期由台风暴雨诱发的坡积层滑坡灾害事故众多,给当地人民生命财产安全造成巨大威胁。斜坡单体风险评价是地质灾害治理与防控的重点、难点。在野外调查、工程地质钻探及岩土体力学测试的基础上,以仕阳镇仕阳北坡为例,结合气象资料分析了不同降雨条件下斜坡的稳定性;采用蒙特卡洛方法计算了斜坡安全系数的统计特性;基于斜坡破坏概率研究了承灾体的易损性,并定量计算了不同降雨条件下建筑物及人员的风险值。结果表明：随着降雨强度的增加,滑坡发生概率随之增加,其风险值也逐渐增加,特大暴雨工况风险最大,其人员风险为94人/年,经济风险为1.41亿元/年。研究结果对东南沿海地区该类滑坡的防治工程有重要的参考意义,可为该类滑坡的防灾减灾决策提供建议。     

东南沿海地区玄武岩残积土雨水运移特征及滑坡失稳数值模拟

暴雨作用下,东南沿海地区玄武岩残积土滑坡极易失稳,但相关的研究较为少见。文章以浙江省温州市马济头滑坡为对象,首先利用原状土土柱实验,获取中峰型和前峰型降雨工况下玄武岩残积土的雨水运移特征;然后使用Geo-studio软件反演土柱降雨实验,获取玄武岩残积土的非饱和渗透参数;接着通过数值模拟,获取两种降雨工况下马济头滑坡的渗流场及稳定性。结果表明:降雨作用下,玄武岩残积土的浅层土体含水率增长速率较快,上部及深部土体更易达到饱和;10 mm/h降雨强度下,湿润锋下渗速率较小且不随深度变化;30 mm/h降雨强度下,湿润锋下渗速率可增大2~3倍,雨水主要在峰值降雨期快速入渗;降雨作用下,马济头滑坡的滑带土饱和度迅速增大,孔隙水压力随之增大,坡脚出现大面积滞水,土体抗剪强度急剧降低,模拟降雨第三天,滑坡的稳定性系数降至最低,滑坡最终失稳;中峰型降雨工况下雨水入渗速率更快,坡脚处产生更大滞水面积,滑坡更容易失稳。本文的研究成果可为东南沿海玄武岩残积土滑坡的稳定性评价提供理论依据。     

川藏公路前-龙段Ⅰ#滑坡稳定性评价及治理建议

川藏公路前-龙段位于二郎山东坡，天全河上游，全长22．8km。该段河谷深切、地形陡峻、雨量丰沛、灌木丛生，线路沿河流右岸逆流而上。1994年该段公路进行技术改造，在改造过程中，大部分路段裁弯取直，下挖降坡，以直接切坡方式通过岩性破碎、构造复杂的区域。由于破坏了原坡体的稳定性，加之雨季施工，因而相继发生了大柏牛崩塌、严江坪滑坡、门坎山滑坡、鸳鸯崖滑坡、龙胆溪滑坡。1997年雨季，此段又发生了1#、2#及3#滑坡。其中，1#滑坡范围大、危害严重、滑体十分破碎、戎因复杂、极具代表性：文章介绍了前一龙段地质情况及滑坡分布，重点研究Ⅰ#滑坡，对其稳定性进行详细的分析，得出该滑坡整治工程非常必要、切实可行的，它已经起到了作用的结论。并指出该滑域目前存在的问题及解决办法，总结了山区道路建设地质选线和滑坡治理的原则。     

Structural and geomorphological aspects of the Kat landslides (Tokat—Turkey) and susceptibility mapping by means of GIS

Kat County, which is located in a slope of hilly region and constructed in the side of a mountain along the North Anatolian Fault Zone, is frequently subject to landslides. The slides occur during periods of heavy rainfall, and these events cause destruction to property, roads, agricultural lands and buildings. In the last few decades, a lot of houses and buildings have been damaged and destroyed. Settlement areas have remained evacuated for a long time. The slope instabilities in the study area are a complex landslide extending from north to south containing a lot of landslides. Field investigations, interpretation of aerial photography, analyses of geological data and laboratory tests suggest that some factors have acted together on the slopes to cause the sliding. In the wet season, the slopes became saturated. As the saturation of the earth material on the slope causesa rise in water pressure, the shear strength (resisting forces) decreases and the weight (driving forces) increases; thus, the net effect was to lower the safety factor. Previous failures have affected the rock mass, leading to the presence of already sheared surfaces at residual strengths. The relation between the joint planes and the instability of the slope in the study area was discussed and it was found that the potential slope instabilities are mainly in the directions of NW–SE, NE–SW and N–S. The landslide susceptibility map obtained by using the geographical information system showed that a large area is susceptible and prone to landslides in the northern part of the study area.An erratum to this article can be found at     

Study of shaking table test of seismic subsidence loess landslides induced by the coupling effect of earthquakes and rainfall

Light rain or moderate rain is the most common meteorological event in the rainy season in the loess area of China, so the probability of landslide hazards induced by the coupling effect of earthquakes and rainfall under the condition of light rain or moderate rain is relatively higher than that under heavy rain. To study the dynamic response characteristics and instability mechanism of loess slopes by the coupling effect of earthquakes and rainfall under the conditions of moderate rain and light rain, a low-angle slope model test of a large-scale shaking table after 10 mm of rainfall was carried out. By gradually increasing the dynamic loading, the evolution of the macroscopic deformation and the instability failure mode of the slope model are observed; the temporal and spatial trends of the amplification effect, acceleration spectrum, pore pressure and soil pressure are analyzed; and the failure mechanism of the slope is determined. The results showed that the amplification effect increased along the slope surface upward, and a strong amplification effect appeared at the front of the top of the slope. Because of the stronger dynamic stress action on the upper part of the slope, the immersed soil in the upper part of the slope experienced seismic subsidence deformation, the saturation in the seismic subsidence soil increased, and the water content temporarily increased locally. With the further increase in the loading intensity, a large number of tension cracks were generated in the seismic subsidence area, and water infiltrated down along the cracks and the wetting range expanded under dynamic action. The range of seismic subsidence and cracks further extended to the deep part of the slope. Under the reciprocating action of the subsequent ground motion, the swing amplitude of the soil mass in the seismic subsidence area, which is divided by a large number of cracks in the upper part of the slope, increased further, resulting in the further reduction in the residual strength of the seismic subsidence soil mass located at the crack tip due to the pull and shear action. Finally, under the combined action of gravity and dynamic force, the upper soil mass in the seismic subsidence area dragged the lower soil mass in the seismic subsidence area downward because the sliding force is greater than the residual strength of the soil mass, which induced a seismic subsidence-type loess landslide. Under the coupling effect of earthquakes and rainfall, the instability mode and mechanism of this landslide are significantly different from those of liquefaction-type landslides.

     

陕西省宝鸡市地质灾害发育特征

根据近7年来陕西省宝鸡市12区县地质灾害详细调查资料,总结宝鸡地区地质灾害主要类型、空间分布规律、发育特征及其危害性。研究结果显示,宝鸡市地质灾害发育类型主要包括滑坡、崩塌、泥石流及不稳定斜坡等4类,总体发育特征具有群发性、突发性、周期性和链生性。其中,滑坡和崩塌数量多、危害大,泥石流相对发育较少,不稳定斜坡多与崩塌相伴生,大多发展为崩塌灾害。每年汛期在强降雨作用下,都可能诱发表层小型滑坡和崩塌,特别是城镇居民房前屋后的小型黄土滑坡和崩塌,以及山区公路切坡导致的残坡积层滑坡崩塌频繁发生,是宝鸡市地质灾害群测群防和减灾防灾关注的重点。     

渗透性与降雨强度对堆积层滑坡稳定性的影响

本文基于非饱和渗流理论及非饱和土的Fredlund双应力变量强度理论,对一沿岩土接触面滑动的堆积层滑坡模型,分别进行了8种条件下的降雨入渗数值模拟试验,研究了不同土体渗透性及降雨强度对滑坡稳定性的影响。结果表明:(1)堆积层滑坡的稳定性与土体的渗透性有密切关系,在降雨后的短期内,土体渗透性越好,滑面孔隙水压力升高越明显,滑坡的稳定性降低程度越大;(2)降雨期间,埋深较浅的滑面,入渗雨水能够较快到达,对滑坡稳定性的影响较大;(3)在相同的降雨时间内,降雨强度越大,滑坡稳定性降低速率越快;(4)降雨强度影响着滑坡发生的滞后性,在降雨总量一定的条件下,若降雨强度较大,雨停后,滑坡稳定性继续下降的程度较大;(5)降雨总量控制着滑坡的最终稳定性。     

Seasonal effects of rainfall on the shallow pyroclastic deposits of the Campania region (southern Italy)

The shallow deposits of unsaturated pyroclastic soils covering the slopes in the Campania region (southern Italy) are systematically affected by various rainfall-induced slope instabilities. The type and triggering of these instabilities depend on several factors, among which in situ soil suction—as an initial condition—and rainfall—as a boundary condition—play a fundamental role. Based on the available database—which includes a comprehensive catalogue of historical data, in situ soil suction measurements and soil laboratory tests along with the results of geomechanical analyses—this paper discusses the relationships among in situ soil suction and rainfall conditions and induced slope instability types. The goal is to reach a better understanding of past events and gain further insight into the analysis and forecasting of future events. In particular, the paper outlines how the season strongly affects the spatial distribution and the type of slope instability likely to develop. For example, erosion phenomena essentially occur at the end of the dry season and originate hyperconcentrated flows while first-time shallow slides prevail in the rainy season and later propagate as debris flows or as debris avalanches.     

降雨入渗条件下软岩边坡稳定性分析

降雨条件下软岩边坡的失稳模式是进行边坡处治的基本依据之一。为研究软岩边坡在降雨条件下的稳定性,提出了一种既能考虑渗流场对边坡稳定性的影响,又能体现岩石软化效应对边坡失稳所带来的不利作用的新方法。运用二维渗流数值计算方法,对降雨条件下的边坡孔隙水压力大小及暂态饱和区面积在空间及时间上的分布进行了模拟。并将渗流场计算结果与暂态饱和区岩石软化试验所得岩石物理力学参数随时间的取值相结合,采用强度折减法分析软岩边坡在降雨入渗条件下的稳定性。对算例边坡的研究表明：降雨入渗条件下软岩边坡的失稳在降雨初期表现为边坡表层局部分层垮塌。随着降雨历时的增长,失稳形式则表现为局部分层垮塌与整体滑移相结合。降雨停止后,边坡负孔隙水压力的消散,对软岩边坡安全系数的继续降低具有一定的延缓作用。     

Landslides in the North of Lisbon Region (Portugal): Conditioning and triggering factors

Detailed geomorphological mapping carried out in 5 sample areas in the North of Lisbon Region allowed us to collect a set of geological and geomorphological data and to correlate them with the spatial occurrence of landslide. A total of 597 slope movements were identified in a total area of 61.7 km², which represents about 10 landslides per km².The main landslide conditioning factors are: lithology and geological structure, slope angle and slope morphology, land use, presence of old landslides, and human activity.The highest landslide density occurs in Cretaceous marls and marly limestones, but the largest movements are in Jurassic clays, marls and limestones.The landslide density is higher on slopes with gradients above 20 °, but the largest unstable area is found on slopes of 10 ° to 15 °, thus reflecting the presence of the biggest slope movements. There is a correlation between landslides and topographical concavities, a fact that can be interpreted as reflecting the significance of the hydrological regime in slope instability.Concerning land use, the highest density of landslides is found on slopes covered with shrub and undergrowth vegetation.About 26% of the total number of landslides are reactivation events. The presence of old landslides is particularly important in the occurrence of translational slides and complex and composite slope movements.20% of the landslide events were conditioned by anthropomorphic activity. Human's intervention manifests itself in ill-consolidated fills, cuts in potentially unstable slopes and, in a few cases, in the changing of river channels.Most slope movements in the study area exhibit a clear climatic signal. The analysis of rainfall distribution in periods of recognised slope instability allows the distinction of three situations: 1) moderate intensity rainfall episodes, responsible for minor slope movements on the bank of rivers and shallow translational slides, particularly in artificial trenches; 2) high intensity rainfall episodes, originating flash floods and most landslides triggered by bank erosion; 3) long-lasting rainfall periods, responsible for the rise of the groundwater table and triggering of landslides with deeper slip surfaces.     

Stability investigation of hill cut soil slopes along National highway 222 at Malshej Ghat,Maharashtra

The section of about 12 km of National highway 222 passing through the Malshej Ghat experience frequent slope failure due to complex geological condition, heavy rainfall and slope geometry. The area is part of Western Ghat Deccan trap and slope masses are made of basalt and its weathered crust (debris/soil). The soil slope failure problem mainly occur in rainy seasons due to induced pore water pressure and reduced strength of the slope mass. The present study has been carried out to investigate the slope forming material and assess the stability of soil slopes by numerical approach. For the identification of the vulnerable zones, field study has been carried out and five vulnerable soil slopes identified namely MGS1, MGS2, MGS3, MGS4 and MGS5 on the basis of degree of weathering and slope geometry. The laboratory experiments were carried out to determine the strength properties of the geomaterials. All the input variables acquired from the field and laboratory experiments have been used for numerical simulation, which was performed with the help of limit equilibrium method (LEM) and finite element method (FEM). Numerical analysis provides understanding of the slope behaviour and illustrates that MGS1 and MGS3 are stable slopes, MGS2 and MGS4 are critically stable, whereas, slope MGS5 is unstable. This study recommend the protection of soil slopes and suggest that more detailed investigation is required for long term remedial measures to prevent risk of damage in Malshej Ghat.     

Finite element modeling approach to assess the stability of debris and rock slopes: a case study from the Indian Himalayas

Landslides and slope failures are recurrent phenomena in the Indian Himalayas. The study area comprises the hill slopes along a road stretch of 1.5 km at a distance of 9 km from Pipalkoti on Chamoli–Badrinath highway (NH-58) in the Garhwal Himalayas, India. Based on the field survey, contour map, and the hillshade, the study area has been divided into different zones. Three different zones/slopes in this study area including one potential debris slide, one stable debris slope, and one potential rock slide have been undertaken for investigation and modeling. Field mapping, data collection related to slope features and soil/rock sample collection, and discontinuity mapping for all the slopes have been carried out in field. Soil samples have been tested in the laboratory to determine the physico-mechanical properties. These properties along with some material properties from the literature have been used as input parameters for the numerical simulation. To investigate the failure process in the debris/rock slides as well as stable debris slope, the slopes were modeled as a continuum using 2D finite element plain strain approach. Shear strength reduction analysis was performed to determine the critical strength reduction factor. The computed deformations and the stress distributions, along the failure surface, have been compared with the field observations and found to be in good agreement. The analysis results indicated rock/debris slide slopes to be highly unstable. The debris slide modeling depicted failures both above and below road levels as observed in field. The rock slide modeling could depict the exact pattern of failure involving 3 sets of discontinuities simultaneously as observed in real-field scenario which is a major limitation in case of limit equilibrium analysis. The field-observed stable slope comes to be stable through FE analysis also. Based on these analyses, landslide hazard assessment of the study area could be done.     

Stability analysis of laterally confined slope lying on inclined bedding plane

A stability analysis of a laterally confined slope model, lying on an inclined bedding plane, was presented to evaluate the lateral shear resistance by considering the loading paths and failure envelopes. Two slope models were prepared on a bedding plane by compaction, one with and one without lateral confinement. The compacted models are related to the geological conditions at shallow depths where brittle deformation can occur and an excavation can induce horizontal field stress that significantly influences the stability of the slope. Three distinct loading paths, controlled by either tilting the angles or increasing the surcharge loads, were applied to achieve the failure of the slope models. Rankine’s passive earth pressure due to compaction was reduced by the shear strength reduction ratio. The shear strength reduction ratio was estimated through the least-squares fitting method based on the results of model tests at failure when the loading paths intersected the failure envelope. Provided that the effect of lateral confinement in a rock mass can be described by the shear strength reduction ratio, the proposed equations will be beneficial for slope stability analyses of laterally confined slopes on bedding planes. A case study of an undercut pit wall in an open-pit mine was demonstrated by showing that the unknown shear strength reduction ratio can be back-analyzed from the rainfall-induced landslide case. Therefore, the design of other undercut slopes with different geometries and groundwater conditions in the rock mass, which have undergone the same geological process as the back-analyzed case, is possible.

     

A deep-seated slow movement controlled by structural setting in marly formations of Central Italy

The site investigation of low-gradient slopes composed by marly rocks usually focuses on shallow slides in weathered mantling material as it is assumed that the underlying bedrock has higher strength, but deeper investigations may reveal larger, active, deep-seated movements. A typical example of this is found in Montemartano (Perugia, Central Italy). Here aerial photo interpretation and field observations indicate that active movements involve the shallower portion of the slope, formed by a very old and large landslide body extending over an area of about 0.5 km². Borehole core logging and probe inclinometer monitoring reveal that the area corresponding to the deep-seated landslide is moving at a maximum rate of 70 mm/year down to a maximum depth of 40 m. A comparison of inclinometer and piezometer data indicates that the movement seasonally reactivates even when rainfall and piezometer levels are below average values and suggests that structural setting of the whole slope influences both groundwater flow and movement kinematics. This hypothesis is reinforced by seepage analyses and stability analyses yielding a mobilized shear strength close to residual strength of the clayey interbeds of the marly limestone formations. This implies that instability occurs along bedding over a large part of the slide. The importance of these phenomena in land management policy is discussed and the critical aspects of their investigation and monitoring are addressed. The reconstruction of landslide geometry/stratigraphy and geotechnical characterization of the materials is closely considered, particularly as these are complicated by the limited representativeness of field and laboratory investigations in this type of material.     

Rock slope stability and excavatability assessment of rocks at the Kapikaya dam site,Turkey

This paper presents the slope stability and excavatability assessment of rocks at the Kapikaya dam site that contains diabases. Both field and laboratory studies were carried out. The field study involved detailed discontinuity surveys. Laboratory tests were carried out to determine uniaxial compressive strength, Young's modulus, unit weight, point load strength index and shear strength parameters of discontinuities.Kinematical and numerical analyses were performed to determine right and left slopes at the dam site. According to kinematical analyses, the types of planar and wedge failure are not expected at the site. Also, shear strength reduction analyses was carried out using Phase² for the right and left slopes at the dam site. According to results of numerical analysis, Strength Reduction Factor (SRF) of the right and left slopes are 8.08 and 6.5 respectively and any rotational failure will not occur. The excavation category of the diabases was determined as easy ripping for the right slope and easy-hard ripping for the left slope.     

Incorporating hydro-mechanical coupling in an analysis of the effects of rainfall patterns on unsaturated soil slope stability

Rainfall-induced landslides can cause loss of life and damage to property, infrastructure, and the environment. Rainfall patterns affect the pore-water pressure of unsaturated soil slopes, and are related to the slopes’ stability. Four rainfall patterns were chosen to represent natural rainfall patterns for an examination of rainfall infiltration into soil slopes using numerical models incorporating coupled water infiltration and deformation in unsaturated soils. Our analysis showed that rainfall patterns play a significant role in the distribution of the pore-water pressure in soil slopes, and influence the slope stability. The pore-water pressure profile of soil slopes and the factor of safety are affected by the ratio of rainfall intensity and the coefficient of permeability. The depth and shape of the shallow sliding plane of the landslide is closely related to the rainfall pattern; moreover, the results showed a correlation between the factor of safety of the slope and the rainfall intensity. This relationship can be described by a dimensionless rainfall intensity. The nonlinear relationship can be used to estimate the slope stability resulting from rainfall infiltration when the hydro-mechanical coupling in unsaturated soil slopes is considered.     

湘西陈溪峪滑坡变形机理及稳定性评价

浅层滑坡在我国广泛分布,但在区域范围内分布规律性较差,且具有突发性、隐蔽性和破坏性强等特点。湘西武陵山区地质条件复杂、降雨丰沛、人类工程活动强烈,突发性地质灾害频发,尤以降雨诱发的浅层滑坡为主。文章以湘西地区慈利县陈溪峪滑坡为例,开展了降雨量、基质吸力、地下水位和地表变形等的监测;结合滑坡的现场调查及监测成果,分析滑坡的形成条件和变形机理;在此基础上,考虑基质吸力对边坡稳定性的贡献,将强度折减有限元法推广到非饱和土边坡,计算得到了不同降雨工况下滑坡稳定性。结果表明:当强降雨降落到滑坡体上时,坡内基质吸力值均迅速减小,直至一定值后（9.5 kPa左右）不再变化;坡内地下水位受季节性降雨影响显著,短时强降雨引起地下水变化幅度不如长时间降雨对地下水位造成的影响大;陈溪峪滑坡的地质力学成因为蠕滑推移式土质滑坡,运动形式为沿基覆界面的浅层滑坡;短时强降雨是诱发滑坡变形的最关键因素。陈溪峪滑坡在持续降雨条件下的降雨量预警值约为280 mm,在短时强降雨条件下的降雨强度预警值约为240 mm/d。     

基于小流域的地震扰动区降雨型滑坡泥石流危险性评价方法

地震扰动区存在大量震裂松散坡体,在持续或者密集的降雨条件下极易转化为滑坡灾害。同时,滑坡又会给泥石流提供大量松散固体物质,增加泥石流的危险性。因此,在震区,灾害通常以"链"的形式出现,比单一灾种危害性大。为了更有效地对地质灾害危险性进行评价,笔者将滑坡、泥石流作为灾害链,综合地加以分析和研究。选择5·12汶川大地震中受灾严重的都江堰市白沙河流域的17条泥石流沟作为研究区,建立滑坡-泥石流危险性评价耦合模型,研究24 h不同降雨量条件下小流域滑坡泥石流危险性的变化。耦合模型包括了坡体稳定性评价模型,水文模型及以泥石流规模、发生频率、流域面积、主沟长度、流域高差、切割密度、不稳定斜坡比为评价因子的泥石流危险性评价统计模型。研究结果表明:随着降雨量的增大,参与泥石流活动的松散物质方量持续增加,但当24 h降雨量超过200 mm后,泥石流沟的危险度等级不再发生变化;17条泥石流沟中4条为中危险度,12条为高危险度,1条为极高危险度。这说明研究区地质灾害问题相当严峻,在多雨季节存在泥石流群发的可能性,直接威胁到居住在泥石流沟附近的人民群众生命财产安全;因此,对于有直接危害对象的高危险度及其以上的泥石流沟,应该按照高等级设防标准进行工程治理及发布预警报。同时也说明,将滑坡、泥石流作为灾害链研究具必要性和可行性。