关键词: 半干旱区, 煤炭开采, 土壤水, 时序监测

Abstract:

Soil moisture content is an important factor affecting vegetation growth in semi-arid areas. The study on effects of coal mining on soil moisture dynamics may help reestablish vegetation in the mining area.Profile soil moisture probes were used to monitor changes in soil moisture content (SMC) in the 10 to 100 cm soil layer of the compression area located at the 52303 working face of the Daliuta coal mine before and after the mining operation. Analysis of the monitoring data shows that before the mining operation, SMC remained quite stable and didn't change much with temperature. In the initial period of the coaling operation SMC changed, but the change was not significant and lagged temporally behind the process of mining. The time lag reached 4-5 days, that is to say, the change in SMC became apparent 4 to 5 days later after the mining operation reached right beneath the monitoring site. Then subsidence began to develop till maximum. During the course it disturbed the soil mass, causing changes in SMC, which rose first and then fell. The disturbance of mining to SMC waned gradually with soil depth in the soil profile from top to bottom. The disturbance of the soil mass caused by subsidence also led to decrease in soil particle size, increase in bulk density and decline of void ratio, thus enhancing the water holding capacity of the soil mass, which explains why SMC rises temporarily in the initial period of the mining operation. Meanwhile the occurrence of ground fissures and reduced water supply from rainfall are the two major causes that lower SMC in the late period of the operation.

Key words: semi-arid area, coal mining, soil moisture, time sequential monitoring