A realistic prediction of excess pore water pressure generation and the onset of liquefaction during earthquakes are crucial when performing effective seismic site response analysis. In the present research, the validation of two pore water pressure (PWP) models, namely energy-based GMP and strain-based VD models implemented in a one-dimensional site response analysis code, was conducted by comparing numerical predictions with highquality seismic centrifuge test measurements. A careful discussion on the selection of input soil parameters for numerical simulations was made with particular emphasis on the PWP model parameter calibration which was based on undrained stress-controlled/strain-controlled cyclic simple shear (CSS) tests carried out on the same sand used in the centrifuge test. The results of the study reveal that the energy-based model predicts at all depths peak pore water pressures and dissipation behaviour in a satisfactory way with respect to experimental measurements, whereas the strain-based model underestimates the PWP measurements at low depths. Further comparisons of the acceleration response spectra illustrate that both the strain- and energy-based models provide higher computed spectral accelerations near the ground surface compared with the recorded ones, whereas the agreement is reasonable at middle depth.

This paper presents an efficient two-and-a-half dimensional (2.5D) numerical approach for analysing the long-term settlement of a tunnel-soft soil system under cyclic train loading. Soil deformations from train loads are divided into shear deformation under undrained conditions and volumetric deformation from excess pore water pressure (EPWP) dissipation. A 2.5D numerical model was employed to provide the dynamic stress state owing to the moving train load and the soil static stress state by the gravity effect for the determination of their accumulations. Then, an incremental computation approach combined with the initial strain approach in the framework of the 2.5D model was developed to compute the long-term deformation of the tunnel-soft soil system, considering the influence of the soil hardening due to EPWP dissipation. This approach helps to determine the distribution of the progressive settlement, transverse and longitudinal deformations in the tunnel-soil system, overcoming traditional limitations. A comparison of settlements computed using this approach with measured settlements of a shield tunnel in soft soil shows good agreement, indicating the effectiveness of the proposed approach in analysing train-induced progressive deformation of the tunnel-soil system.

This paper presents a method to predict the impact of underground tunnel construction on nearby piles using non-linear soil-pile-tunnel interaction. Two stage analysis method have been used considering Kerr foundation model. Greenfield ground settlements have been compared with site-specific instrumentation data of East-West Metro Project, Kolkata, India and results obtained were found to be in good agreement. It has also been observed that the Kerr foundation model considers soil spring over Pasternak's model and hence yields reduced pile deflection compared to Pasternak's model. Non-linear analysis considers non-linear stress-strain relationship and so yields more pile deflection than linear analysis under large deformation. Validation has been performed with case studies in published literature. Irrespective of end conditions, critical bending moment in pile develops at the tunnel centreline depth and at the fixed ends. Soil is a non-elastic material and due to its own shearing strength, the soil also absorbs some portion of the ground deformation before transferring that to the pile. So, consideration of non-linear Kerr model captures a realistic response of the pile. An accurate and cost-effective solution method of non-linear tunnel-soil-pile interaction model has been developed for easy application by practicing engineers using MATLAB software which is commonly available in most of the design.

Wall piers are widely used to enhance lateral stability in bridges with tall piers and relatively narrow decks. For this type of structure, the longitudinal direction of the bridge is commonly acknowledged as the governing direction for seismic performance, with wall piers serving as the seismic critical members. However, progressive scouring reduces foundation strength and stiffness, leading to increased transverse seismic deformation. This deformation amplifies the risk of pile damage and may shift the seismic critical member to the foundation. This study investigates the seismic performance of wall pier bents in bridges, explicitly focusing on the effects of riverbed scouring. Through a Taiwan-based case study, seismic performance is evaluated at various scour depths, identifying the seismic critical member through capacity spectrum analysis and the peak ground acceleration corresponding to the performance limit of the wall pier bent. The findings highlight that seismic performance is frequently controlled by the transverse direction, emphasizing the foundation as the seismic critical member. The effect of employing foundation strengthening as a retrofit strategy is also assessed, revealing that it provides only limited improvement in seismic performance. Even after retrofit, the seismic performance of wall pier bents remains primarily governed by the pile foundation.

The cactus pear (Opuntia ficus-indica) is a crucial plant in Tigray, northern Ethiopia, widely distributed in arid and semi-arid environments. It serves as a seasonal food, and is used in livestock feed, fencing, soil conservation, and environmental protection. Recently, the cactus pear populations in Tigray have been severely affected by an exotic insect, the cochineal (Dactylopius coccus). It damaged cactus pear populations in the region's southern, southeastern, and eastern zones. The Tigray war that broke out in November 2020 exacerbated D. coccus infestation. A study was conducted in the eastern zone of Tigray to assess the impact of the armed conflict on the trends of this infestation and propose sustainable management approaches for sustainable cactus pear production in post-war Tigray. Both primary and secondary data were collected and analyzed. The findings revealed that D. coccus infestation significantly increased during the war and in the post-war period, compared to in the pre-war period. The number of districts involved and level of D. coccus infestation of cactus pear populations increased. The rapid spread was attributed to the interruption of pest management activities due to the armed conflict. To mitigate the spread and ensure sustainable cactus pear production, this study recommends different management approaches to manage D. coccus dissemination and sustainably produce cactus pear in the region, including pest prevention, suppression, or eradication.

The constitutive model is essential for predicting the deformation and stability of rock-soil mass. The estimation of constitutive model parameters is a necessary and important task for the reliable characterization of mechanical behaviors. However, constitutive model parameters cannot be evaluated accurately with a limited amount of test data, resulting in uncertainty in the prediction of stress-strain curves. This paper proposes a Bayesian analysis framework to address this issue. It combines the Bayesian updating with the structural reliability and adaptive conditional sampling methods to assess the equation parameter of constitutive models. Based on the triaxial and ring shear tests on shear zone soils from the Huangtupo landslide, a statistical damage constitutive model and a critical state hypoplastic constitutive model were used to demonstrate the effectiveness of the proposed framework. Moreover, the parameter uncertainty effects of the damage constitutive model on landslide stability were investigated. Results show that reasonable assessments of the constitutive model parameter can be well realized. The variability of stress-strain curves is strongly related to the model prediction performance. The estimation uncertainty of constitutive model parameters should not be ignored for the landslide stability calculation. Our study provides a reference for uncertainty analysis and parameter assessment of the constitutive model.

Due to the impact of climate change and human activities, part of the Yongding River has stopped flowing, and the hydrological environment is damaged. The hydrological condition can be used to assess the ecological environment of the watershed, and analyzing the driving factors affecting the hydrological condition is essential for the environmental restoration of the watershed, but it is particularly challenging on a daily scale. This paper used the Indicators of Hydrologic Alteration and the Range of Variability Approach (IHA-RVA) method to screen out the sensitive indicators in different periods that are representative of each river; determined the hydrological variation periods of the upper Yongding River and the two subbasins, the Yang River and the Sanggan River; and quantitatively identified the contribution of climate change and different human activities (water withdrawals and reservoir storage) to the basin's runoff by constructing a daily-scale model named the Water and Energy Transfer between Soil, Plants, and Atmosphere (WetSpa) model. The results showed that the upper Yongding River, the Yang River, and the Sanggan River had a high degree of variation (87.2%), a low degree of variation (20%), and a moderate degree of variation (37.5%) in 1975-1988, 1980-1986, and 1978-1993, respectively. Human activities were the main driving factors, but their contributions varied across different basins. The Yang River is mostly affected by water withdrawals, with a contribution rate of 125.90%. The Sanggan River was affected mostly by reservoir storage, with a contribution rate of 153.47%. The upper Yongding River was affected mostly by climate change. A stricter management system can reduce the impact of human activities on runoff changes and provide a guarantee for the restoration of the ecological environment of the upper Yongding River.

The current Indian Standard Seismic Code IS 1893: Part 1 (2016) for general buildings lacks detailed guidelines on modeling soil-structure interaction (SSI) in the estimation of seismic demand and earthquake-induced damage in reinforced concrete buildings. Therefore, this study aims to investigate the effects of SSI, with a focus on its nonlinear behavior, on the seismic demand of ductile reinforced concrete frames designed as per IS 1893: Part 1. The selected RC buildings are designed for second-highest seismic risk zone in India and represent short, medium, and long-period structures commonly found across Indian sub-continent. The influence of SSI is studied for soil type II and type III, as specified in the Indian Code, which corresponds to medium stiff and soft soil sites, respectively. Using a nonlinear Winkler-based model, numerical finite element models of linear and nonlinear SSI have been developed for isolated shallow foundations. This study utilizes the results of incremental dynamic analysis to evaluate the fragility parameters for code specified performance limit states. Further, the estimated fragility parameters are integrated with the regional hazard curve coefficients to quantify the annual exceedance probability of specified damage levels. The simulation results highlight the critical impact of nonlinear SSI on the earthquake resilience of IS code designed low- to high-rise reinforced concrete buildings. Notably, the percentage increase in estimated fragilities is higher for low-rise buildings than high-rise buildings when subjected to ground motions on soil sites. Additionally, the vulnerability to failure of these buildings elevates significantly when they are analyzed on soft soil sites compared to medium soil and bedrock sites. Therefore, it is recommended to account for the significance of nonlinear SSI while assessing the expected structural performance and fragility of IS 1893: Part 1 designed stiff low- to medium-rise reinforced concrete buildings, as this step can substantially enhance the resiliency of such buildings in the aftermath of a disastrous earthquake.

The shutdown of earth pressure balance (EPB) shield tunneling in gravel stratum can easily lead to significant unexpected ground deformation. In order to study the response of gravel strata during shield shutdown and the characteristic change of soil state in the chamber, this paper establishes a coupled Eulerian-Lagrangian finite element method (CEL-FEM) coupling analysis model that reflects the interaction between the spoiled soil and gravel strata. The plastic flow parameters of CEL spoiled soil are calibrated using the slump method, and a quantitative relationship between the slump value, plastic flow parameters, equivalent coefficient of loosening, and excavation face support pressure is established. The reliability and applicability of CEL method in the simulation of shield shutdown are verified by the field measurements. Results show that: (1) The chamber's soil equivalent loose coefficient is inversely proportional to the soil slump value which is related to soil's plastic flow parameters. (2) The shield shutdown in gravel strata has a more significant impact on the deep strata displacement than on the surface. (3) During the shield shutdown stage, the chamber pressure should be dynamically adjusted based on the soil deformation characteristics, and an increase of 16% could result in a stable rebalance.

The cone penetration tests have been employed extensively in both onshore and offshore site investigations to obtain the strength properties of soils. Interpretation of effective internal friction angle gyp' becomes complicated for cones in silty clays or clayey silts, since the soil around the advancing cone may be under partially drained conditions. Although there exist several robust methods to estimate gyp ' , the pore pressure at the cone shoulder has to be measured to represent the drainage conditions. Many cone penetrometers in practice are not equipped with a pore pressure transducer. Even for a piezocone, the pore pressure recorded in-situ may be unreliable due to the poorly saturated or clogged filter. These limitations prohibit the application of existing methods. Large deformation finite element analyses were carried out within the formula of effective stress to reproduce the cone penetrations under various drainage conditions. The numerical approach was validated against the existing model tests in centrifuge and chamber, with wide ranges of penetration rates and soil types. A backbone curve is proposed to estimate the normalized cone resistance varying with the normalized penetration rate. Based on the backbone curve, a procedure is developed to predict gyp' of cohesive soils under undrained or partially drained conditions, replacing the pore pressure with the normalized penetration rate. The procedure can be used for soils with an overconsolidation ratio no larger than 5.