Automated geotechnical monitoring in construction of running tunnels in subways under operating railroads

Abstract

The city of Moscow is currently faced with the extremely aggravating problem connected with traffic. Hereupon, majority of transportation systems are being expanded and upgraded. Construction of new running tunnels and subway stations, road spans, crossovers, underground parking lots, etc. is in process. The new construction affects the existing development sites in the time of surplus fallout, which leads to emergency situations. It is required to provide geotechnical monitoring of soil mass in the influence zone of new construction. To this effect, the wireless online monitoring system has been designed and introduced into surveillance of building structures and soil mass. The system is meant for the integrated and continuous observation of a control object. The operation charts and advantages of the wireless monitoring system are presented. The introduction experience of the automated geotechnical monitoring in the process of construction is described. The observation of a railroad overpass used the tilt sensors and crack meters. The deformation monitoring in soil mass was carried out using borehole deviation devices and extensometers. It is demonstrated that the time of the measurement cycles is related with the position of the shield tunneling face relative to the measurement boreholes. The interpreted data analysis proves correlation of the measured and predicted deformations. The deformation propagation in depth of soil mass is characterized. The data analysis made it possible to predict deformations of ground surface and, thereby, to eliminate a potential accident during shield tunneling under the surface railroad.