In situ approach for monitoring changes of rock stresses induced by rock excavation of the permanent shiplock in the Three Gorges Project, China

Measurements of rock stress changes induced by rock excavation were presented to be one of the main works involved in the structure safety monitoring during the rock excavation of the permanent shiplock in TGP. Three different kinds of monitoring instruments were accepted as the basic methods available for monitoring changes of rock stresses. They are YOKE gauges imported from Australia, Piezoelectrical stress gauges and Piezomagnetic stress gauges. Some of these instruments had being working in field for more than two and half years. This paper presents the performance of these instruments used in situ for monitoring changes of rock stresses in TGP, and the problems related to the long term monitoring works are discussed.