The additional load caused by vehicles is an important consideration in the design of highway retaining structures. This study investigated the additional earth pressure of retaining wall caused by vehicle load. Combined with the construction of a cantilever retaining wall in the Liandu-Jinyun section of 330 National Highway Expansion Project, a series of soil pressure boxes was embedded above the floor of the retaining wall and on the inside of the vertical plate. After the wall was constructed, a 30 t dump truck was used as the load source and asked to stop at designated places, the additional vertical and lateral earth pressure caused by vehicles (static load) was tested, and the test results were compared with the calculated results obtained using the standard uniform distribution method in the current highway design code and the Boussinesq solution of elastic mechanics. Results reveal that the additional lateral earth pressure along the wall shows a nonlinear distribution, the maximum value appears in the middle of the wall, and the peak value decreases as the distance of the truck from the retaining wall increases. The distribution pattern of additional vertical earth pressure on the floor in the cross-section direction is also non-linear. Agreat difference exists between the measured and calculated results. Using the uniform distribution method to determine the additional lateral earth pressure caused by the vehicle load may underestimate the bending moment or anti-overturning moment resulting from the additional lateral earth pressure, which may cause failure of the anti-bending and anti-overturning abilities of the retaining wall to meet the requirements. For the variable section retaining wall (the wall section size decreases with the wall height), the shear strength of the middle and upper parts of the wall may be insufficient, and shear failure may occur. The tested additional lateral earth pressure is basically the same as the Boussinesq solution, but the vertical additional earth pressure is larger than the Boussinesq solution. This study suggests the use of the Boussinesq solution with multiple lanes and standard vehicles as the additional load caused by vehicle when designing the retaining wall (especially heavy duty road retaining wall).

Based on the subgrade project of Jiyuan-Xin'an Expressway, a field test of compaction and reinforcement of high-fill loess embankment was designed and conducted, the reinforcement effects and influence depth of two reinforcement schemes, namely dynamic compaction and impact rolling, were discussed, and the finite element method was used to further optimize the construction parameters for the impact rolling scheme with better field reinforcement effect. The results show that the influence depth of dynamic compaction reinforcement ranges from 4 to 6 m, while that of impact rolling reinforcement ranges from 2 to 4 m. Within the influence depth range, the reinforcement effect of soil improves with an increase in dynamic compaction or rolling times, but the increase gradually decreases, indicating an optimal dynamic compaction or rolling time. According to the construction parameters of the in-situ test, impact rolling reinforcement after a 2-m fill height is more effective in improving the compaction degree and uniformity of the subgrade compared to dynamic compaction reinforcement after a 4-m fill height. The influence depth of impact rolling reinforcement increases with the rolling time, reaching up to 3 m after 20 times. Both the compaction effect and influence depth increase with the mass of the impact wheel but first increase and then decrease with an increase in the traveling speed of the impact wheel. The optimal traveling speed of the impact wheel is 3 m/s.