1. Settlement observation timing: may be handled according to regulations.

2. The commonly used method for surface settlement observation in construction sections is to embed settlement plates in the original ground for elevation observation.

3. Settlement plates are embedded in the foundation at the road center, shoulders, and slope toes. A settlement plate consists of a steel or reinforced concrete base plate, a metal measuring rod, and a protective sleeve. The base plate dimensions shall be no less than 50cm×50cm×3cm; the measuring rod diameter should preferably be 4cm; the protective sleeve dimensions should be such that it can encase the measuring rod and allow the staff to enter the sleeve. As the fill height increases, the measuring rod and sleeve shall be extended accordingly, with each section preferably not exceeding 50cm in length. After extension, the top surface of the measuring rod should be slightly higher than the upper opening of the sleeve; the upper opening of the sleeve should be capped to seal the pipe opening, preventing fill material from falling into the pipe and affecting the freedom of the measuring rod to settle. The cap top should not be more than 50cm above the compacted surface.

4. Settlement plate observation shall use S1 and S3 type levels, employing geometric leveling with Class II medium precision requirements for elevation measurement; the observation precision shall be less than 1mm.

5. Observation foundation piles: displacement marker piles used for observing horizontal displacement and calibration datum piles are also used simultaneously for settlement observation. Marker edge piles embedded at the slope toe and beyond generally also measure ground settlement. A semicircular measuring head engraved with a cross line should be pre-embedded on the top of the marker pile.