ENGINEERING-GEOLOGICAL CHARACTERISTICS OF SUBSIDING LOESS ALONG MAIN LINE OF THE PROJECT OF DIVERTING WATER FROM YELLOW RIVER AT WANJIAZAI,SHANXI,AND ENGINEERING TREATMENT OF TUNNEL DEFORMATION AND FAILURE

The tunnel of main line of the Project of Diverting Water from Yellow River at Wanjiazhai, Shanxi, passes largely through subsiding loess, which is mainly upper Pleistocene eolian loess. Field geological inverstigation and laboratory geotechnical test permitted us to understand the physical and mechanical properties and deformation of the subsiding loess. Analyzing the characteristics and regularities of the wet subsidence of loess, we discuss the causes for defects in construction of the tunnel and suggest a scheme of reasonable engineering treatment for ensure the unimpeded water flow.