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Controls of Water Movement and Transform in Yungang Grottoes,Datong,China

Author: ChaiLiJie
Tutor: WangXuSheng
School: Chinese Geology University (Beijing)
Course: Groundwater Science and Engineering
Keywords: Yungang Grottoes Water source Controlling factors Migration
CLC: P641
Type: Master's thesis
Year: 2011
Downloads: 78
Quote: 2
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Abstract

Flooding and surface differentiation has become a threat to the important issues of the stone relics in China. Yungang Grottoes in Datong cut in the sandstone to Seibu State Shannan cliffs, stone carvings in the caves facing the weathering damage continued to increase. The various sources of water is one of the grottoes carved weathering caused the most direct and the most fundamental factor, the fundamental way to solve the grotto carved continue weathering the the accurate detection Grottoes internal moisture into the channel. In this paper, the investigation and analysis to identify the control factors for a variety of water sources, to provide a scientific basis for the grotto flooding governance. The main water sources in the Yungang Grottoes Grottoes or cave wall directly seepage, the cave wall mudstone perched water infiltration, air condensate. The main factors affect 窟顶 seepage rainfall, silt layer thickness, 窟顶 fractured situation. More stagnant water permeability of the silt layer is far below the sand and gravel, and silt. The survey showed that silt infiltration by rain precipitation than in any part of the infiltration to the bedrock at the top of the only in thin silt area to infiltration into the bedrock at the top. Infiltration to the the bedrock top of the water is closely related to the ability to enter the cave with the development of cracks at the top of bedrock. The sandstone top surface of the average annual infiltration minimal precipitation and more runoff and evapotranspiration excretion. The perched water quantity and mudstone size and distribution. Precipitation infiltration coefficient increases with increasing coefficient of precipitation infiltration. The north-south cross-sectional view of mudstone contact with caves, can easily form a perched water excretion from the cave. Control condensate generated temperature, ground temperature, air humidity, wind speed and other factors, the Yungang Grottoes Cave lower wind speed throughout the year, so the impact of the main factors for the temperature difference between the air temperature and the ground temperature and air humidity condensate condensation water generated. The summer temperatures and the temperature difference between the ground temperature and the humidity is also high, easy to produce condensate, small temperature difference between winter and the humidity is low and difficult to produce condensate. Cave outer wall temperature difference between the air temperature and the ground temperature is small, generally does not produce condensate. Closely related to the degree of weathering of the condensation of water and the rock face on the cliffs, rock faces with high degree of weathering, weathering in sandstone porosity increases, increased the weathered rock wall than fresh rock wall condensation surface greater combined rock wall The internal temperature than the surface temperature is low, weathered rock wall than fresh rock wall can condense more condensate water.

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