Interlayer shear weakness zone has a series of features such as loose structure

easy to be softening

large spatial distribution and poor mechanical properties in Baihetan hydropower station. The existence of interlayer shear weakness zone seriously affects the stability of underground cavern groups of hydropower station. In order to reveal and improve the mechanical properties of interlayer shear weakness zone

X-ray diffractometer

scanning electron microscope and mercury intrusion porosimetry tests are applied separately to observe and determine the main mineral composition

the orientated range of particles and the distribution of pore structure in samples. Microstructural properties of interlayer shear weakness zone and its effect on the selection of grouting materials are discussed in detail combining with the testing data. What’s more

chemical modification experiments are carried out based on above experiments. Comparative experiment between samples immersed with or without sodium silicate solution indicates that chemical modification can improve the integrality

elastic wave velocity

compressive strength

elastic modulus and cohesion of interlayer shear weakness zone effectively. These cognitions can provide some useful means for the engineering reinforcement and modification design of interlayer shear weakness zones in Baihetan hydropower station.