Landslide & Slope Stability

Slopes Give Warning Before They Fail

According to USGS research, rainfall is the primary trigger for slope failure. A slope’s vulnerability builds gradually, weakening over months or years before a rainfall event raises pore water pressure to the point of failure. By the time visible signs appear on the surface, the warning window may already have passed.

Under Singapore’s Building Control Regulations, instrumentation and monitoring plans are a statutory requirement for geotechnical works involving slopes. BCA requires qualified persons to determine appropriate monitoring of pore water pressures, water table levels, and ground deformation with defined instruments, frequencies, and reporting. Wetec designs and supply slope monitoring systems that meet these requirements, integrating multiple data streams into a single automated early warning system.

USGS research identifies rainfall thresholds as the most common forecasting tool for landslide occurrence. But a complete slope monitoring system goes beyond rainfall to track the subsurface conditions.

• Rainfall — intensity and accumulation monitored continuously against slope-specific thresholds.

• Pore water pressure — the primary mechanical trigger for rainfall-induced failure. Rising pore pressure reduces effective stress and signals deteriorating stability before any surface sign appears.

• Ground movement and displacement — total stations, inclinometers, tiltmeters, extensometers, and crack meters detecting subsurface and surface movements that precede failure.

All data streams feed into a secure, remotely accessible platform. When any parameter crosses a defined threshold, automated SMS and email alerts are sent to the responsible person and the relevant team — in time to act, not only to respond.