Volume Loss
The volume loss method is a semi-empirical method based partially on theoretical grounds. The method introduces, although indirectly, the basic parameters of excavation into the analysis (these include mechanical parameters of a medium, technological effects of excavation, excavation lining etc) using 2 comprehensive parameters (coefficient k for determination of inflection point and a percentage of volume loss VL). These parameters uniquely define the shape of subsidence trough and are determined empirically from years of experience.
Settlement expressed in terms volumes
The maximum settlement Smax, and location of inflection point Linf are provided by the following expressions:
where: | A | - | excavation area |
Z | - | depth of center point of excavation | |
k | - | coefficient to calculate inflection point (material constant) | |
VL | - | percentage of volume loss |
The roof deformation ua follows from:
where: | r | - | excavation radius |
VL | - | percentage of volume loss |
Literature:
http://www.groundloss.com/