Self-drainage anchor cable system for slope protection and construction method thereof

A construction method for a self-drainage anchor cable system, comprising steps of:

• (1) through slope engineering geological condition investigation, analyzing a location of a potential sliding surface, a depth of a groundwater level of a slope and a groundwater level line to be controlled;
• and drilling a borehole at an appropriate position of the slope to enter a location below the potential sliding surface and the groundwater level line;
• (2) determining a diameter and a quantity of steel strands according to an anchoring force required by an anchor cable;
• (3) modifying a length of a permeable pipe to equal a length of a drainage section, and modifying a length of an isolation pipe to be larger than the length of the drainage section;
• sleeving both ends of the isolation pipe with water stop rings made of water-expanding rubber, and sleeving the isolation pipe with the permeable pipe, wherein end portions of the permeable pipe are in contact with the water-expending rubber water stop rings;
• (4) manufacturing an anchor cable body, and installing the isolation pipe together with the permeable pipe and the water stop rings made of the water-expanding rubber into the drainage section above an internal anchoring section;
• (5) sleeving the drain pipe with a protection pipe, in such a manner that the drain pipe passes through holes of the water stop rings made of the water-expanding rubber and extends into a space between the permeable pipe and the isolation pipe, and a water inlet of the drain pipe is at a bottom of the drainage section;
• (6) after the water stop rings made of the water-expanding rubber are fully expanded with water, filling the borehole with cement mortar, and performing anchor cable tensioning and locking pre-stress;
• and
• (7) when a water head height of the water inlet of the drain pipe is greater than an elevation of the borehole, discharging groundwater by the drain pipe under a water head difference, which starts a siphon drainage process and generates a negative pressure in the space of the drainage section, in such a manner that the groundwater in the slope accelerates into the drainage section;
• after draining the groundwater of the slope, in-taking air through the water inlet of the drain pipe, in such a manner that suction and discharge of the drain pipe disappears, and an entire drainage process ends;
• wherein with cycles of rainfall infiltration, the drainage process circulates.