金沙江下咱日堆积体的成因和稳定性初步分析

PRELIMINARY ANALYSIS OF FORMATION MECHANISM AND STABILITY OF AN ACCUMULATION BODY AT XIAZANRI ABOVE LIYUAN WATER HYDROPOWER STATION ON JINSHA RIVER

下咱日堆积体的稳定性对拟建的梨园水电站大坝和附近的水力设施有着重要的意义。利用下咱日堆积体的勘察资料,本文分析后认为下咱日堆积体经历了中更新世的金江冰期和晚更新世的丽江冰期两次冰期的作用,是由冰碛物、河流沉积物、湖相沉积物及崩积物组成的复杂成因堆积体;稳定性初步分析认为,下咱日堆积体局部有坍塌,但是整体稳定,以后稳定与否的关键是堆积体中湖相沉积层及坡脚的松散砾石层的稳定性。

Stability of the accumulation body at Xiazanri is very important to the establishments of the Liyuan hydropower station on the Jinsha River. This station is to be built.. Based on field reconnaissance material of the Xiazanri accumulation body, the paper studies its formation mechanism and stability. The results show that it is a complex accumulation body which comprises moraine, alluvium, lake sediment and colluvium and has gone through 2 ice ages, i. e. , the Jinjiang ice age in middle pleistocene/rod the Lijiang ice age in middle Pleistocene. The resuits of stability assessment show the Xiazanri accumulation body is stable as a whole despite it can have some partial failings. The key factors controlling whether it will be stable or instable are the stabilities of the loose gravel layer at the slope toe and the lake sediments.