Self-boring pressuremeter (SBPM) tests are widely used in situ investigations, due to their distinct advantage to measure the shear stress-strain-strength properties of the surrounding soil with minimum disturbance. The measured pressuremeter curve can be interpreted using analytical solutions based on the long cylindrical cavity expansion/contraction theory with relatively simple constitutive models, to derive useful soil properties (e.g., undrained shear strength of clay, shear modulus, and friction angle of sand). However, the real soil behavior is more complex than the assumed constitutive relations, and the derived parameters may differ from those obtained using more reliable lab tests. In addition, SBPM tests can be affected by other well-known factors (e.g., installation disturbance, limited length/diameter ratio, and strain rate) that are not considered in the analytical solutions. In this paper, SBPM tests are evaluated using finite-element analysis and the MIT-S1 model, a unified constitutive model for soils, to consider complex soil behavior more realistically. SBPM tests in Boston Blue Clay and Toyoura sands are simulated in axial symmetric and plain strain conditions, and the computed results are interpreted following the suggested procedures by analytical solutions. The derived parameters are compared with those from the stress-strain relations to evaluate the reliability of SBMP tests for practical application.

The construction of diaphragm wall panels inevitably changes the initial stress condition and causes movements in the surrounding soil mass, which may also cause settlement and damages to adjacent buildings. Majority of current design and analyses of deep excavations assume that the diaphragm wall is wished-in-place, largely because of the complexities involved to consider the detailed wall installation process. Limited studies suggested that neglecting the wall installation effects would reduce the reliability of these analyses for both predictions and validations. This paper analyzes measured ground response and building settlements caused by diaphragm wall panel installation and highlights the importance of considering these installation effects in practical design. A realistic modeling procedure is then developed to incorporate the sequential diaphragm wall panel construction process in braced excavation analyses, to investigate the installation effects on adjacent ground and buildings. The computed results are consistent with those field measurements from different case studies. The benefits of the proposed approach are demonstrated though comparison with the conventional wished-in-place approach in the braced excavation analyses.

Stiff in-ground structural or diaphragm walls have previously been used as a liquefaction countermeasure for existing building structures. The available design methodologies for typical mitigation techniques are based on free-field conditions, disregarding seismic interactions among soil layers, mitigation, foundation, and superstructure. In this paper, we use three-dimensional (3D) fully-coupled nonlinear finite-element analyses, validated with centrifuge test results, to evaluate how the properties of structural walls (SWs) in layered liquefiable soils affect the seismic performance of a potentially inelastic structure on mat foundations. The SWs were shown to reduce foundation's permanent settlement in most cases (although not to acceptable levels), at the expense of its peak transient and residual tilt. However, SWs amplified the foundation's settlement in cases involving a thick, dense draining crust (Hcrust >= 4m) or a uniform and thick medium to dense sand layer. Increasing the wall's penetration into the lower dense sand layer and its flexural stiffness were shown to be effective in reducing foundation settlement by reducing shear-type deformations within the critical layer. Simultaneously, increasing the foundation-to-SW distance amplified settlement by increasing the potential for accumulation of shear strains. For the cases considered, foundation tilt was relatively insensitive to changes in wall geometry and flexural stiffness. Overall, Hcrust was the most influential parameter for mitigation effectiveness in terms of permanent settlement and tilt, followed by the relative density of the critical layer. The limited numerical sensitivity study presented in this paper shows that SWs may not always benefit the overall performance of the soil-foundation-structure system, and their design requires consideration of system and ground motion characteristics with great care.

Tunnels offer myriad benefits for modern countries, and understanding their behavior under loads is critical. This paper analyzes and evaluates the damage to buried horseshoe tunnels under soil pressure and traffic loading. To achieve this, a numerical model of this type of tunnel is first created using ABAQUS software. Then, fracture mechanics theory is applied to investigate the fracture and damage of the horseshoe tunnel. The numerical analysis is based on the damage plasticity model of concrete, which describes the inelastic behavior of concrete in tension and compression. In addition, the reinforcing steel is modeled using the bilinear plasticity model. Damage contours, stress contours, and maximum displacements illustrate how and where traffic loading alters the response of the horseshoe tunnel. Based on the results, the fracture mechanism proceeded as follows: initially, damage started at the center of the tunnel bottom, followed by the formation of damage and micro-cracks at the corners of the tunnel. Eventually, the damage reached the top of the concrete arch with increasing loading. Therefore, in the design of this tunnel, these critical areas should be reinforced more to prevent cracking.

In the laying of long-distance pipelines, it is sometimes impossible to avoid one or more areas that are prone to frequent geological disasters, such as landslides. In the case of such a disaster, the buried pipeline is likely to undergo large displacement leading to plastic deformation, subsequent leakage, explosions, and other accidents that may result in its failure. In order to ensure the safety of pipeline transportation, in this work, a remote real-time system for monitoring the status of pipelines was designed on a cloud service platform to realize stress-strain analysis and to provide an early warning of pipeline damage after a landslide. The results of the stress-strain analysis of a pipeline buried under a landslide were used to establish a numerical calculation model based on the shell element and nonlinear soil springs. The deformation distribution characteristics of the pipeline, based on multiple factors, were studied, and the effects of the landslide width, buried depth, ultimate soil resistance, diameter thickness ratio, and internal pressure on vertical displacement, as well as the axial strain and bending strain of the pipeline were obtained. According to the results of the finite-element method, the plastic deformation position of the pipeline under the action of landslide was determined, the software and hardware configuration of the pipeline strain monitoring scheme was designed, and the installation of the pipeline strain monitoring system was carried out. The processing results of the field data showed that the model had a good noise reduction effect. Moreover, the results showed that the system achieved stable real-time data acquisition, efficient data remote transmission, convenient operation, and rich terminal monitoring capabilities, thus effectively providing an evaluation of the operating status of the pipeline, improving landslide disaster warning, and ensuring the safe operation of the pipeline. Buried pipelines are likely to undergo large displacement under the action of geological disasters such as landslides, which can lead to accidents such as pipeline leakage and explosion. In order to ensure the safety of pipeline transportation, a numerical calculation model of a buried pipeline based on shell elements and soil springs is established to analyze the stress and strain of a pipeline under a landslide. The model can reflect the deformation distribution characteristics of the pipeline and analyze the influence of landslide width, buried depth, and other factors on the deformation of the pipeline. Based on the presented method, the dangerous points of plastic deformation of pipeline under landslide can be determined. Furthermore, combined with the actual situation of a landslide site, a monitoring system has been designed and installed that can operate stably for a long time in the landslide disaster site. The system can realize the acquisition, transmission, and evaluation of pipeline data, and ensure the smooth operation of buried pipelines.