泥石流异重流入海的研究

Research on Debris Flow into the Sea as a Density Flow

1999年委内瑞拉瓦加斯 (Vargas)乌里亚 (Uria)发生的大规模泥石流将海岸线向海中推进了 2 0 0m。这是一种异重流现象。泥石流流入海中并在海中沉积下来 ,其头部沉积位置距原海岸线已远大于 2 0 0m。泥石流在海中的沉积物还将改变海底地貌。本文通过实验研究得出了异重流的潜入点规律。

The debris flowed into the sea and pushed the coastline of Uria into the sea for 200 meters in the debris disaster of Vargas, Venezuela in December 1999. It was a density current phenomenon. The debris flowed into the sea and deposited in the sea. The head of stratified debris was far more than 200 meters from the ex-coastline. The debris was in high concentration and high density. It moved in intermittent, when debris stopped, the density current stopped at once. Stratified debris in experiments flowed into a pool with 6m long and 3m wide, and the bottom slope is 2%. The density ratio of debris and water were 1.2, 1.3, 1.4, 1.5, respectively. Experiments was finished in dry pool and different level of water. The plunging point of stratified debris was observed and the plunging law was gotten. The stratified debris flowed into the pool and deposited a fan, which had two parts: one was exposed on the water, and the other was under the water. The height of deposition in water is larger than the height in air. By comparing the deposition, the characteristics of fan on the water and under the water of stratified debris have been obtained.