In 1972, as part of the upgrading of the North Circular Road (A40) in Neasden, an anchored diaphragm wall was constructed in heavily over-consolidated London Clay and instrumentation was installed to monitor the performance of the wall. In 1988, additional instrumentation was installed to better investigate the longer term performance of the wall. The results of the study have been reported by Carswell et al (1991). Although a number of the instruments have failed in-service, the remaining operating instruments include load cells to measure the loads in the ground anchorages, spade cells to measure lateral stresses in the ground, inclinometers to monitor ground movements, and piezometers to measure pore water pressures. Following the work of Carswell et al (1991), the instruments have been read sparingly throughout the 1990s but more regular monitoring recommenced in 1998. This report provides an update of the performance of the anchored wall. (A)
Abstract