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The process of rill erosion causes significant amounts of sediment to be moved in both undisturbed and disturbed environments and can be a significant issue for agriculture as well as mining lands. Rills also often develop very quickly (from a single rainfall event to a season) and can develop into gullies if sufficient runoff is available to continue their development. This study examines the ability of a terrestrial laser scanner to quantify rills that have developed on fresh and homogeneous mine spoil on an angle of repose slope. It also examines the ability of the SIBERIA erosion model to simulate the rill's spatial and temporal behaviour. While there has been considerable work done examining rill erosion on rehabilitated mine sites and agricultural fields, little work has been done to examine rill development at angle of repose sites. Results show that while the overall hillslope morphology was captured by the laser scanner, with the morphology of the rills being broadly captured, the characteristics of the rills were not well defined. The digital elevation model created by the laser scanner failed to capture the rill thalwegs and tops of the banks, therefore delineating a series of ill defined longitudinal downslope depressions. These results demonstrate that an even greater density of points is needed to capture sufficient rill morphology. Nevertheless, SIBERIA simulations of the hillslope demonstrated that the model was able to capture rill behaviour in both space and time when correct model parameters were used. This result provides confidence in the SIBERIA model and its parameterization. The results demonstrate the sensitivity of the model to changes in parameters and the importance of the calibration process. Figure 2. Photograph of the study site (top) with a digital elevation model (0·2 m by 0·2 m grid) (bottom). This figure is available in colour online at www.interscience.wiley.com/journal/esplFigure 3. Initial hillslope used for the SIBERIA simulations. The digital elevation model grid size is 0·2 m by 0·2 m.Figure 4. Site layout showing scanner locations. Results Laser scanning of the slopeProximity to the studied slope was limited by the pond immediately in front of the slope. Initially, the instrument was set up at a location on the other side of the pond, approximately 300 m directly in front of the slope (Figure 4). This initial scan, while successfully capturing the gross morphology of the slope, generated a point cloud that was too sparse in relation to the rills. A second scan was done at a distance of approximately 100 m, but offset to the right of the slope (Figure 4). This location enabled the whole slope to be scanned at a higher resolution, and still without the presence of holes in the dataset created by features in the foreground obscuring more distant objects (known as 'occlusion effects ';Lim et al., 2005;Lichti and Gordon, 2004).I-Site was programmed so that it scanned the slope and surrounding area. This produced a point cloud consisting of approximately 76 000, points with the...

Despite the significance of rockfall hazards in Australia, this phenomenon is still poorly characterized in many regional environments. In particular, the relationship between slope/rock properties and rockfall motion parameters needs to be better defined. In the context of rockfall prediction, it is important to quantify the normal and tangential restitution coefficients (referred to as k n and k t) and the equivalent rolling coefficient (µ), which are site-specific. Several series of rockfall tests have been conducted in three different geological environments in New South Wales. The results of the tests show a large variability of the motion parameters, which is due to the natural variability of the blocks and to the randomness of the impact positions. Also, values of k n consistently and systematically higher than the benchmark values from the literature have been inferred. Despite there being no clear correlation between the restitution coefficients and the rotational energy, this latter is believed to be at the origin of such results.

Injection of expansive polyurethane resin can be used to remediate differential settlement issues. The resin is injected incrementally under a structure to achieve a desired foundation level, forming a composite resin–clay material. This solution is not well documented in the literature and some questions arise on the long-term performance of this solution. As injection is usually carried out in a settled soil mass that is dry and dessicated, rehydration of the soil after injection may lead to swelling of the leveled foundation and overlifting of the structure. Experimental research undertaken to investigate this rehydration issue and determine if there is a risk of overlifting in the long term is presented here. In situ and laboratory testing was performed to investigate the most fundamental aspects of the problems. This included the in situ injection of resin, study of resin propagation in the soil mass, influence of resin on the hydraulic conductivity of the soil mass, and large-scale swelling tests. The results suggest that, even though the resin cannot prevent the rehydration of the soil mass, the risk of overlifting in the long term is limited.