Description: The monitoring system consists of a Campbell Scientific, Inc. CR1000 data logger in a weatherproof enclosure. The enclosure also houses a voltage regulator and back-up battery for the 12-V DC system. Connected to the data logger are two tiltmeters and an AVW4 vibrating wire interface with two VWPs attached to it. The data logger is programmed to read the voltage output from two tiltmeters and the two VWPs. The program converts the voltage from the tilt meters to the degree of tilt and the actual movement of the top of the wall in inches. It also converts the voltage from the VWPs to the hydrostatic head behind the wall in units of feet. The tiltmeters are securely fastened on mounting brackets and are located on top of the retaining wall. The two VWPs are grouted approximately 4.5-ft into the lower part of the retaining wall. Communications are by means of an Airlink Raven 110 GPRS IP addressable modem using a dynamic IP address acquired through the CrossBridge Imotient “tunnel.”
Location: San Luis Obispo County, California
