HYDROCONSOLIDATION AND SUBSIDENCE OF LOESS - STUDIES FROM CHINA, RUSSIA, NORTH-AMERICA AND EUROPE

Various approaches to the widespread problem of the hydroconsolidation and subsidence of loess have been suggested. These include considerat ions of rheology, thermodynamics, phase movements, particle packing, i nterparticle bonding, pore structure and distribution, catastrophe the ory, topology, and simple structural frameworks. Chinese, North Americ an and most European investigators tend to concentrate on mechanisms o f loess collapse. The Russian literature, however, retains an extra di mension. Two approaches, the 'syngenetic' and the 'epigenetic' approac h, to the formation of subsiding loess have been defined in the litera ture. Most investigators follow a syngenetic approach which appears to be a consequence of the aeolian idea of loess deposition. Some Russia n writers, in contrast, promote an epigenetic approach in which collap sibility can develop in an originally noncollapsible material, which c an then suffer from hydroconsolidation and subsidence. The basis of th e phenomenon is a change in the packing structure of the major loess p articles, and this can be modelled using simple Monte Carlo methods to develop appropriate structures. This paper aims to review the work do ne on this important subject. Serious investigation of hydroconsolidat ion and subsidence of loess began in the early nineteen-forties, fifty years ago, and this has been reported in a piecemeal manner. A detail ed, critical review of this diverse work is now overdue and this is pr esented herein in the light of recent work in the United Kingdom. An a ttempt is made to describe the process in a phenomenological and a str uctural sense. Inherent in this, the role of N. Ya Denisov as 'subside nce pioneer' is considered.