ENGINEERING PROPERTIES AND SUB-CLASSIFICATION OF HIGHLY WEATHERED GRANITE WITH ABUNDANT WATER AND THE GRADING

Intensely weathered granite stratum is widely distributed in southeast, coastal areas of China, this paper focus on its regional and variable engineer performance. Based on the background of mining excavation of shallow tunnel - Xiamen Airport Road, using the methods of in-situ observation and soil test, studies the mineral content mechanics character and water stability of the intensely weathered granite, gave the sub-classification of weathered granite and the corresponding engineering measures. The results show that the water stability of intensely weathered granite was instability, and its shear strength is related with the water content. If the water content was lower than 14%, the cohesion high and the friction angle will be very low; as the water content increasing to the plastic limit, the cohesive strength will be increased obviously; but when the water content was higher than the plastic limit, the angle of internal friction reduced rapidly because the inside pore was thread together. According to the sub-classification of rock, different engineering measures for different sub-classified rock can be taken, this make the construction better.