Typical view of China's typical landslide
One. landslide
1. The large landslide in Tiantai Township, Xuanhan, Sichuan
The landslide occurred on September 5, 2004, induced by heavy rain. 1255 people were affected, 2,983 houses were destroyed and 1,097 acres were destroyed. It belongs to the bedrock landslide. The plane shape is "circle chair" shape, the longitudinal length is 950 ~ 1200m, the horizontal width is 1400 ~ 1600m, and the area is 1.2km2. The sliding bed is mainly sandstone , and the rear is steep and the shape is slow. The front part slides in the same layer, the slope is 5O~7O, the rear part is cut, the slope is gradually 20O~40O, and the main sliding direction is 95O. The sliding body is mainly composed of purple-red silty clay mudstone and mudstone fractured rock. The thickness is generally 7~49m, the average thickness is 23m, and the total volume of the sliding body is 25 million m3. About 2.1 million m3 of deposits are washed into the river. .
Panoramic overview of the landslide disaster area in Tiantai Township, Xuanhan, Sichuan
Remote sensing image of landslide and river backwater
“3D†remote sensing image before landslide
“3D†remote sensing image after landslide
The front part of the landslide rushed into the front river and raised the riverbed by 23~28m, causing serious blockage of the river channel, forming a barrier lake with a returning water length of 15km and a storage capacity of 58 million m3. Inundated the upstream Wubaochang Town and the 5 banks of 8 villages along the banks of the river, with 4,930 mu of farmland, and urgently transferred 19,360 people affected by the disaster.
Landslide flooded upstream villages and towns
Analysis of the Landscape and Disaster Causes of the Extraordinary Landslides in Tiantai Township, Xuanhan County, Sichuan Province
Landslide front profile
The front edge of the landslide is cut into the river, and the groundwater seeps out along the slip zone.
The landslide cuts out into the river, forming a landslide dam
Into the river landslide body to form a barrier lake
The landslide underlying landslide sandstone is a layered fractured rock mass with good water solubility.
Landslide
Landslide landslide is a sandstone mudstone interbed structure
Landslide cylinder
Residual landslide cylinders show the original thickness and structure of the landslide
Landslide deformation, tree skew
Landslide deformation and cracking to form drunken forest
The paddy field water seeps into the landslide body, which promotes the deformation and rupture of the landslide.
Deformation of the landslide, the depression of the paddy field
The rice fields were destroyed, and the infiltration of the water intensified the sliding
The pond was destroyed, and the infiltration of the pool caused the sliding to intensify.
2. Three Gorges Project Wufengshan landslide in Yunyang Old County, Chongqing Reservoir Area
The landslide occurred on January 17, 2001, and fell from the elevation of 607.7m, and cut along the elevation of 570m, and led to the landslide of the old landslide debris, which piled up on the 380-410m elevation. The volume is about 30,000 m3. Endangered the safety of more than 12,000 lives and property. The landslide protolith is the middle-thick layer of quartz siltstone interbedded mudstone in the second member of the Suining Formation. The slope of the terrain and the dip angle of the strata are nearly identical, ranging from 48O to 54O. The fissures of the layer and the longitudinal and lateral joint fissures are developed. The leading edge conditions are good and the front Groundwater overflows from the edge of 360m. After the landslide occurred, the local government quickly organized the relevant units to carry out emergency treatment to ensure the safety of people's lives and property during the Spring Festival and the flood season.
Yunyang old county landslide: The old county seat is located on the Xicheng landslide body, and the back mountain is Wufengshan landslide.
Wufengshan landslide poses a serious threat to the life and property of more than 12,000 people in the old county seat
Wufengshan landslide transforms into mudslide, posing a threat to the lower residents
Analysis of the Landscape and Disaster Causes of the Wufengshan Landslide
Wufengshan landslide slides along the monoclinic rock layer
The surface of the Wufengshan landslide is dense, forming a slippery body with a thickness of several meters.
Monoclinic strata consist of mudstone and sandstone interbeds
"Sandwich" slope poses a threat to the upper building
The superficial layer of rock and soil forms a "saber tree" under creep
The superficial layer of rock and soil is under the water-bearing rock layer, and the rainy season is easy to form a bedding slip.
The landslide body accumulates on the slope, posing a threat to the lower county seat
The relevant units used reinforced concrete anti-sliding block to prevent landslide debris flow from harming the county town. The old tires were laid at the leading edge of the intercepting project to slow down the debris flow impact piles. At present, the residents in the lower part of the blocking project are in safety.
Disaster prevention measures taken by the relevant units
3. The Three Gorges reservoir area is inclined to the slope
Yunyang-Fengjie develops a series of landslides along the two wings of the Yuanling, including the old landslides such as the old county, the pagoda and the Qiangtang.
Fengjie Qiantang Giant Landslide
Fengjie Qiantang giant landslide front edge anti-dip platform
Yunyang old county Ping landslide
"Gravity Die Casting. A permanent mould casting process, where the molten metal is poured from a vessle of ladle into the mould, and cavity fills with no force other than gravity, in a similar manner to the production of sand castings, although filling cn be controlled by tilting the die."
Gravity Die Casting
Sometimes referred to as Permanent Mould, GDC is a repeatable casting process used for non-ferrous alloy parts, typically aluminium, Zinc and Copper Base alloys.
The process differs from HPDC in that Gravity- rather than high pressure- is used to fill the mould with the liquid alloy.
GDC is suited to medium to high volumes products and typically parts are of a heavier sections than HPDC, but thinner sections than sand casting.
There are three key stages in the process.
- The heated mould [Die or Tool] is coated with a die release agent. The release agent spray also has a secondary function in that it aids cooling of the mould face after the previous part has been removed from the die.
- Molten metal is poured into channels in the tool to allow the material to fill all the extremities of the mould cavity. The metal is either hand poured using steel ladles or dosed using mechanical methods. Typically, there is a mould [down sprue" that allows the alloy to enter the mould cavity from the lower part of the die, reducing the formation of turbulence and subsequent porosity and inclusions in the finished part.
- Once the part has cooled sufficiently, the die is opened, either manually or utilising mechanical methods.
Advantages
- Good dimensional accuracy
- Smoother cast surface finish than sand casting
- Improved mechanical properties compared to sand casting
- Thinner walls can be cast compared to sand casting
- Reverse draft internal pockets and forms can be cast in using preformed sand core inserts
- Steel pins and inserts can be cast in to the part
- Faster production times compared to other processes.
- Once the tolling is proven, the product quality is very repeatable.
- Outsourced Tooling setup costs can be lower than sand casting.
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