坝肩变坡引起心墙裂缝和水力劈裂的离心模型试验研究

Centrifuge modeling of cracking and hydraulic fracturing in core dams induced by abrupt change of bank slope

受地形条件的制约,坝肩变坡在土石坝工程中经常出现。坝肩变坡不但会引起心墙裂缝,还会影响坝体的抗水力劈裂能力。结合某高心墙堆石坝工程,进行了相关离心模型试验研究,并对结果进行了计算分析。结果表明:坝肩变坡会使心墙产生不均匀沉降,发生横向裂缝;压实度影响着心墙的不均匀沉降程度,制约着横向裂缝的形态;存在坝肩变坡的心墙在固结中会形成局部低应力区,快速蓄水时有发生水力劈裂的可能。

The differential settlement induced by discontinuous gradient of bank slope is one of the main reasons for transverse cracking and hydraulic fracturing in core earth dams.A series of centrifuge modeling tests and calculations are conducted in this research.The results show that the abrupt change of bank slope can lead to differential settlement which contributes to the transverse cracking in the core dams.The compaction degree of soil is a key factor affecting the formation of transverse cracking and the degree of differential settlement.The hydraulic fracturing owing to the cracks may occur in the core dams with abrupt change of bank slope during rapid reservoir filling.