Current design methods propose that reinforcement loads distribution within reinforced soil slope is affected by slope height instead of slope inclination, which is not supported by the results of field and laboratorial tests. This paper addresses the influence of slope height and inclination on the distribution of reinforcement loads within reinforced soil slopes. Based on centrifuge model test results, finite element numerical models of reinforced soil slopes with different slope heights and inclinations were established. Maximum reinforcement load in each layer was calculated when the factor of safety of each model was 1.3. The influence of slope height and inclination on the distribution of reinforcement loads was analyzed by normalizing reinforcement loads and slope heights. The results show that the computed location and shape of failure surface and factor of safety at slope failure are in agreement with the experimental results. The distribution of reinforcement loads is little influenced by slope height, whereas greatly influenced by slope inclination. With the increase of slope inclination, the location of maximum reinforcement load transfers from the mid height to the bottom of slopes.
This paper presents two new algorithms for real-time calculation of the wheel angles and speeds of gantry tractor modules. In transport mode, the gantry tractor is, in a sense, a snakelike robot with passive joints and active wheels, with each module having autonomous four-wheel drive and four-wheel steering. The algorithms determine the wheel angles and speeds of each module with the prescription that the four wheels will have the same center of curvature, wheel speeds provide cooperative redundancy, and all hitching points follow the same path, thereby eliminating scuffing and minimizing off-tracking. Details of the analytical algorithm for a predetermined path were presented at the 2009 IEEE International Conference on Industrial Technology, together with a simulation for a single module. In this paper, we also present the results of a newly developed numerical algorithm which enables the gantry tractor to be steered online by an operator. We also show, by simulation, that this new numerical algorithm gives a good approximation to analytical solutions. The numerical algorithm is then used to calculate wheel angles and speeds for a three-module tractor with the results depicted graphically as functions of time.