寺坪面板堆石坝趾板软岩基础灌浆试验研究

Experimental research on grouting soft rock foundation under toe slab of Siping concrete faced rockfill dam

在软弱岩体中进行灌浆,难度很大,特别是在面板堆石坝趾板上对软岩地基进行帷幕灌浆,国内工程中设计与施工成功的经验很少。本次灌浆试验针对寺坪水电站大坝坝基软弱岩体的特殊性,研究及探索在中—弱透水性软弱岩层坝基处理中有效提高灌浆压力的方法和工艺。通过采用均布固结、锚杆应力监测、分级升压、抬动自动报警等一系列措施,使趾板基础帷幕第1段最大灌浆压力达到1.0 MPa,浅部幕体抗渗安全系数超过1.90,建构起安全、可靠的面板坝趾板软岩基础防渗体系。

There usually exists great difficulty in grouting soft rock body,especially China has little successful experience in design and construction of curtain grouting in a soft rock foundation with grouting conducted on the toe slab of a concrete face rockfill dam.Grouting tests were carried out in accordance with the characteristics of the soft rock dam foundation at the Siping hydropower station to investigate effective methods and technologies for raising the grouting pressure in the treatment of soft rock dam foundation with medium-weak permeability.A series of measures,such as uniformly arranging grouting holes for consolidation grouting,monitoring stresses of anchor rods,increasing grouting pressure in stages,automatically warning against the upraising of toe slabs,were taken to make the maximum grouting pressure of first section increase to 1.0 MPa and the factor of safety against seepage of shallow curtain bodies exceed 1.90, building a safe and reliable seepage control system for the soft foundation under concrete face rockfill dam's toe slabs.