Heave/settlement points with Borros Anchor are used to monitor settlement in the ground beneath surcharges or embankments. They are also used to monitor heave (uplift) resulting from excavation or grouting. The Borros-type anchor is suitable for soft clays. It is difficult to extend the prongs of the anchor in other types of soil, such as stiff, over-consolidated clays, shales, dense sand, or sand and gravel.
A heave/settlement point with borros anchor consists of a three-pronged anchor, an inner pipe and an outer pipe, both steel. The inner pipe is attached to the anchor and is free to move inside the outer pipe. An optical survey is used to determine the elevation of the top of the inner pipe. Changes in its elevation indicate an equivalent amount of settlement or heave at the anchor.
Borros Anchor Specifications
|The anchor is approximately 14 inches (356 mm) tall. The permanently attached ¼ inch pipe extends approximately 32 inches (813 mm) above the top of the anchor. A special left-hand threaded coupling is included with the anchor|
|Users should obtain the required lengths of ¼ inch and one-inch pipe locally. The anchor has standard NPT threads. Users in UK should order, or obtain locally, BSP to NPT thread adaptors for both the 1-inch and ¼ inch pipes. Users with other size pipes and threads can usually find adaptors to NPT or BSP threads locally|