Although the maintenance work of pavement is often planned based on MCI and FWD data, the repeated damages of pavement are observed at many places. This surface damage of pavement is partly originated by the weakness of subgrade, damage of the filled up ground and ground water. In order to avoid repeated maintenance works of pavement, the condition of earthfill structure should be evaluated by an easy logging technique from pavement surface. The automatic technology for surveys and evaluations of pavement and embankment by using surface wave logging and electric resistivity logging has been proposed. In this study, we tried to improve the pavement life by reinforcing the base course using geosynthetics for degraded pavement on the low embankment with multiple box culverts.

A time-dependent unified displacement function is proposed to capture main deformation responses of the tunnel cross-section. When the expansion order n equals 2, this complete displacement mode is used as displacement boundary condition (DBC) of the tunnel cross-section. Complex variable method is adopted in order to obtain an elastic analytical solution. Considering the time effect of ground mechanical parameters and tunnel cross-section deformation, a viscoelastic analytical solution of ground displacement is obtained. By parametric analyses, time effects of settlement trough curve, ground displacement and the settlement at the center point of ground surface are analyzed.

This paper reports a case study of progressive failure on a high cut slope due to continuous excavation. The characteristics of each stage failure induced by excavation are analyzed through geological investigation and field monitoring. The slope safety situation was monitored and analyzed. The monitoring results provide the important guidance for slope dynamic design and construction. It is important that the reinforcement of pre-stressed anchoring cables for the slope should be carried out after the slope excavation accomplished as soon as possible. Slope construction monitoring plays an important role in ensuring high slope safety. The results revealed that the slope instability was triggered by the continuous excavation of the slope, and the failure mode of slope is progressive sliding.

When vehicles travel through a tunnel or when water flows through it, the gross weight of a tunnel and pressure of the earth acting on the bottom of the tunnel simultaneously increase. This change in earth pressure may induce risks such as ground settlement and ground failure. Additionally the change in the stress state in the vicinity of an underground structure influences the friction between underground structure and the ground to a certain extent. In previous work, authors evaluated surface friction calculated from residual earth pressure at the bottom and lateral earth pressure at the sidewall of an underground structure model that were associated with changes in the weight of the model using laboratory tests. They concluded that residual earth pressure at the bottom corresponded to surface friction acting on the sidewalls of the model. In this study, the earth pressure acting on the bottom and the lateral earth pressure acting on the sidewall of the underground structure model were measured with change in the weight and uplifting of the model. We examined the mechanism of the surface friction between the underground structure and the sandy ground. The results showed that the earth pressure acting on the bottom was affected by the self-weight of the structure as well as the frictional forces acting on the surface of the structure.

The stability of the excavation face plays a critical role in the safety of shield tunnel construction, and the failure mode is one of the most important factors. By using transparent soil materials, it is possible to obtain a more real displacement field of the soil without disturbed. This paper used the transparent soil model tests and numerical simulation, two situations of the single tunnel and the crossing existing tunnel were performed to investigate failure mode of the excavation face. The test results indicated that the failure mode of single tunnel is a bulb-like shape with soil arching effect, and the failure mode of crossing existing tunnel is a wedge shape. In addition, comparing the two cases, the surface settlement of the crossing existing tunnel is significantly reduced. This means that the existing tunnels can weaken the surface settlement.

Stability of slopes where water was accumulated at the toe area during dynamic events were studied in this paper. The soil below and right above water level tended to be contractile and loose due to water storage at the toe of slope, and the slope behaviors became different compared with those without water storage. Several model tests in a geotechnical centrifuge were carried out in this paper to examine the effects of water accumulation at slope toe, relative density of soil, and shaking intensity of dynamic events on the slope stability. The compression of the soil below the water level and localized failure at the toe region subjected slopes to more shearing during shaking and potentially large movements. For the unsaturated slopes with high suction, total collapse was not possible even in model where intense shaking was excited. Successive shaking with increasing intensities could cause more cracks on the surface of the slope, and the deep and wide cracks were mainly on the upper middle part of the slope. Cracks concentrated at areas near the water level. Seepage and capillary flow are two factors that need further attention in the study of the dynamic response of unsaturated slopes with water storage at toe.

Since there are limited literature focused upon the tunnel liner forces response to the very close-proximity tunnelling, a consensus has not yet reached. This study characterised the response of tunnel liner forces to the excavation of soft soil twin tunnels in the very close proximity, with reference to the field measurements and 2D numerical simulations. The “belta” method and the “volume loss” method were to distribute the earth load to the liner and capture the effect of ground loss, respectively, and the “local strain” method was to reproduce the effect of tunnel advance. The predictions were in reasonable agreement with the field measurements except the tunnel invert where the liner might not be in good contact with the surrounding soil. The principle stress change and rotation were analysed. Parametric studies about the joint number and distribution, ground deformability and rotational stiffness of joint were conducted. The critical angles for the distribution of odd number joint were suggested.