美国岩土工程Research Proposal范文：Effect of clay property on landsli

目录

1.背景2

1.1滑坡分类2

1.2山体滑坡的原因5

2.粘土性质的影响6

2.1粘土中水含量的影响6

2.2施加力对粘土的影响8

3.拟议计划9

参考10

1. Background 2

1.1 Classification of landslides 2

1.2 Causes of landslides 5

2. Effect of clay property 6

2.1 Effect of water content within clay 6

2.2 Effect of applied force on clay 8

3. Proposed plan 9

Reference 10

Table of Figures

Figure 1 Schematic diagram for debris flow 2

Figure 2 Schematic diagram for earthflows 2

Figure 3 Schematic diagram for debris slide 3

Figure 4 Schematic diagram for sturzstrom 3

Figure 5 Schematic diagram for shallow landslide 4

Figure 6 Schematic diagram for deep-seated landslide 4

Figure 7 Frequency of landslide vs. mean annual rainfall 7

Figure 8 Landslide frequency vs. slope angle 8

Figure 9 Slope distribution vs. rock type 9

 

Effect of clay property on landslides粘土性质对滑坡的影响

Background背景

1.1 Classification of landslides滑坡分类

滑坡或山体滑坡被定义为地质时代的一种现象，包括各种地面运动，如浅层泥石流，斜坡深度破坏和落石等。山体滑坡在陆上，近海和沿海等地区很常见。重力是滑坡的主要原因，其他因素也影响原始坡度的稳定性。由于前置条件因素而形成的特定条件使得斜坡或区域容易发生故障，并且由于特定条件而触发了实际滑坡的释放。有不同类型的滑坡，深层滑坡，浅层滑坡，sturzstrom，碎片滑坡，地球流动和泥石流。

Landslide or landslip is defined as a phenomenon in geological era including various ground movements such as shallow debris flows, deep failure of slopes and rockfalls etc. Landslides are common in areas like onshore, offshore and coastal. Gravity is the main cause of landslide though, other contributing factors also affect the stability of original slope. Specific conditions built up because of pre-conditional factors make the slope or area prone to failure easily, and the releasing of actual landslide is triggered because of specific condition.There are different types of landslides, deep-seated landslide, shallow landslide, sturzstrom, debris landslide, earthflows and debris flow. 

当斜坡材料被水饱和时，泥浆流被释放，汽车，房屋和树木可能被所产生的泥浆吸收，因此支流和桥梁可能被引起的洪水阻挡。碎片很容易被误认为是暴洪，而实际上却完全不同。阿尔卑斯地区的基础设施和建筑物受到严重破坏，因为泥泞的泥石流也造成了人类的生命。泥石流有时是开始与坡相关的因素造成的，并且可能阻塞河床，这可能会暂时造成水堵。与此同时，由于蓄水的失败也产生了多米诺骨牌效应，并且流量的增加也体现了流量。固液混合物的密度可达2吨/立方米，速度可达14米/秒（Arattano和Franzi，2003年）。第一次严重的道路中断是由于泥石流造成的，因为泥土碎片的影响被低估了。

Debris flow is released when the slope material is saturated with water, the cars, houses, and trees are possibly picked up by the resulting slurry, therefore the tributaries and bridges are possibly blocked by the caused flood. Debris is easily mistaken as flash flood, while they are totally different actually. Severe damage to infrastructure and structures in alpine areas are caused because of the muddy-debris flows, the human lives are claimed also. Debris flow is sometimes the result of starting slope-related factors, and possibly dam the stream beds, which may cause the water blockage temporarily. At the same time, domino effect is created also because of the failure of impoundments, and the increasing of flowing mass’ volume also attributes. Densities up to 2 tons/m3, velocities up to 14 m/s can be reached for the solid-liquid mixture (Arattano and Franzi, 2003). First severe interruption of road is caused for debris flow, and damage happens also because of underestimation of the influence of mud-debris.

Figure 1 Schematic diagram for debris flow

Earthflows move at speed ranges from slow to fast, which consist of viscous flow of fine-grained and saturated materials. Speed range from 0.17 to 20 km/h is typical. Earthflows are similar with the mudflow, while the speed is slower compared with mudflow, and more solid material is contained. They are more different from fluid flows, because of their higher speed. Pyroclastic, fine-grained, silt and fine sand, and clay are all susceptible to earthflows. The water content in the earthflow decides its velocity and higher water content causes higher velocity.

Figure 2Schematic diagram for earthflows

For debris landslide, it is chaotic movement of debris, soil and rocks mixed with ice and/or water. The incoherent mixture of smaller vegetation, broken timber and other debris caused by the saturation of thickly vegetated slopes triggers the debris landslide easily. It is different with debris avalanches, because it is slowerasless water content exists in debris landslide. Debris avalanches cause steep coastal cliffs easily, which happen normally on the oceans island volcanos’ submerged flanks, such as the Cape Verde Islands and Hawaiian Islands. Big rocks initiate the debris landslides firstly, which is the top part of slide and gradually break apart when they slide to the bottom. Thus the debris slides are slower than the debris avalanche, as latter has higher water content, and steeper slope. 

Figure 3 Schematic diagram for debris slide

Sturzstrom is a kind of rare landslide, which is not easy to be understood with long run-out. These slides are usually flowing slowly over low angle terrain, even slightly uphill. 

Figure 4 Schematic diagram for sturzstrom

Shallow landslide is defined as slide with superficial sliding surface from few decimeters to meters. Failures of road out-slopes, debris flow and debris slides are usually included in shallow landslide. The areas that have slopes with low permeable bottom soils under the high permeable soils are where the shallow landslides usually happen. The high permeable soils create high water pressure in the upper soils, as the bottom and low permeable soils trap the water in the shallower. Because of the filled water in the top soils, the slopes are unstable which are prone to slide over the bottom soils which are low permeable. 

Figure 5 Schematic diagram for shallow landslide

As for the deep-seated landslide, the sliding surface is located deeply below the depths of the roots of the trees, which are normally greater than ten meters. Weathered rocks, deep regolith are involved in the deep-seated landslides. This kind of landslide happens usually in the region which is tectonic active like Zagros Mountain in Iran. They move several meters per year, which are very slow. 

Figure 6 Schematic diagram for deep-seated landslide

1.2 Causes of landslides