Soil-nailing technology is relatively new, and there is a need to evaluate the effectiveness of the soil nails as a method of landslide stabilization. Launched soil nails are being increasingly used as an economical and quick method of slope stabilization in many states. The nails are 1.5 inches (3.8 cm) in diameter and 20 feet (6.1 m) long hollow steel or fiberglass bars. The soil-nail launcher forces the nails into the soil at speeds up to 200 miles per hour (322 km/h).;Six landslide sites in Summit County, Ohio, have been stabilized using the soil-nailing method. These sites are the focus of this study to evaluate the effectiveness of launched soil-nails to stabilize landslides.;The following field investigations were completed at the landslide sites: (i) the types and causes of the slope movements were identified, (ii) the location of the failure plane was established, (iii) stratigraphic profiles were established, (iv) soil samples were collected to determine natural water content, dry density, Atterberg limits, and shear strength parameters, (v) photographs were taken to depict various landslide features and the nature of each slope movement, (vi) surfical slope movement was monitored on a monthly basis using pegs at three sites for nine months, and (vii) subsurface slope movement was monitored on a monthly basis using inclinometers at three sites for three months. A stability analysis was performed for each site using GSTABL7 computer software, before and after installation of soil nails.;Laboratory test results indicate that the soils present at the six sites consist of silts and clays. The cohesion values of the samples range from 84 psf to 1068 psf (0.004 MPa to 0.051 MPa), whereas the friction angle varies from 15° to 32°. The modes of failure for the six sites are identified as rotational slides or a combination of rotational slide and flow. The failures are caused by the steepness of the slopes, the fine-grained nature of the soils, development of pore pressure, and the undercutting of the toes by local streams. The surficial movement observed from the peg-line surveys showed a displacement of 0 inches to 8.75 inches (0 to 22.2 cm), and the monitoring of the inclinometers showed negligible movement. The stability analysis shows that soil nailing improved factor of safety values to 1.2 to 3.3.;The purpose of the soil nails is to stabilize the upper portion of the slope and to prevent damage to the pavement and shoulder. The soil nails were deemed effective if no new cracks were observed in the pavement, if no new scarps developed, if no movement was observed of the guardrail, and if the inclinometer data showed no movement. Results of the monitoring show that the upper parts of the slopes that have been stabilized using the soil nails have not moved. Thus, soil nailing is an effective method of landslide stabilization.
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