Accurately characterising the horizontal coefficient of consolidation (Ch) is of paramount importance for the settlement control and serviceability evaluation of deep soft clay foundations, with the cone penetration test with pore pressure measurement (CPTU) dissipation test currently serving as the mainstream in-situ technique for determining this parameter. However, the interpretation accuracy of CPTU dissipation data relies heavily on the idealised assumptions of the chosen theoretical models, rendering model form uncertainty and natural site variability easily confounded during the parameter inversion process. To systematically untangle the multi-source uncertainties in parameter back-analysis, it is highly desirable to quantify the systematic biases of different inference models and their underlying governing mechanisms within a unified probabilistic framework. Leveraging field-measured data from a deep soft clay site, this study establishes a layered Bayesian inversion and comparison framework. The results demonstrate that traditional simplified models based on a single characteristic point suffer from weak data constraints, yielding not only wide posterior uncertainty intervals but also a distinct systematic overestimation bias. Further analysis under a unified t50 target and joint diagnostics shows differentiated model behavior: Burns gives the lowest prediction errors and no significant median bias in the passing subset, Teh–Houlsby provides higher interval coverage, and Torstensson performs weakest. Prior-space and posterior association analyses indicate that uncertainty in the characteristic-time models is mainly linked to time-factor parameters, whereas Burns is more strongly associated with φ’. These findings highlight the need for diagnostic screening, unified cross-model comparison, and cautious interpretation of both central estimates and interval coverage in CPTU dissipation inversion.

Geosynthetics are widely used for reinforcement, and strain monitoring is essential for the safety of reinforced soil structures. This study evaluated the durability of a sensor-enabled piezoelectric geobelt (SPGB) with reinforcement and monitoring functions. Accelerated photo-oxidation and thermo-oxygen ageing tests were conducted to assess changes in mechanical and electrical properties. Ageing reduced tensile strength and elongation at break, with thermo-oxygen ageing causing the greatest deterioration; after 42 days, tensile strength retention and elongation retention decreased to 78.60% and 57.23%, respectively. Normalised impedance showed a stable linear relationship with strain, although ageing slightly reduced impedance sensitivity. Voltage output was only minimally affected, and clear voltage responses were still observed during tensile failure. These results indicate that SPGB retains reliable sensing performance after ageing and can support lifecycle monitoring of reinforced soil structures.

Coastal silty soft soils feature high water content and low bearing capacity, which readily induce large pile-soil differential settlement, amplify negative skin friction (NSF), and compromise foundation safety. To clarify NSF evolution in silty soft soil foundations, four centrifugal single-pile model tests with initial water content of 40%, 50%, 60%, and 70% were conducted to investigate the long-term behaviors of settlement of pile and soil, axial force of pile, NSF and neutral point (NP) under surcharge consolidation. The test results show that the higher the initial water content of the soil, the greater the compressibility. During the 5-year loading consolidation process, the soil settlement and the pile-soil differential settlement increase significantly with the increase of initial water content and consolidation time, which leads to the nonlinear growth trend of the peak value of axial force and the peak value of the absolute value of NSF. In addition, the NP migrates upward over time and essentially stabilizes after 2 years, while the NP shifts downward with increasing initial water content. An empirical equation correlating the initial water content with the NP depth ratio was established in this study, providing reliable data support for the design and construction of coastal pile foundations.

As an underground concealed project, pile foundations are often unable to effectively resist groundwater buoyancy, necessitating consideration of anti-floating measures. Given the limitations of current monitoring technologies in achieving real-time, full life-cycle monitoring of uplift piles, the development of distributed, high-precision, and cost-effective monitoring methods remains a key focus in the field. In this study, a sensorenabled piezoelectric geocable (SPGC) based on flexible piezoelectric sensing is used to monitor the bearing capacity characteristics of uplift piles in a distributed manner. Strain gauges are installed for comparative analysis, and the influences of pile diameter in equal diameter uplift piles and the diameter of the enlarged bottom in enlarged-base uplift piles on their ultimate bearing capacity are investigated. The test results indicate that the variation trend of pile strain obtained from SPGC normalized impedance is generally consistent with that measured by strain gauges, and a linear calculation formula for impedance-strain correlation is established. Significant differences are observed in the axial force and side friction resistance between equal diameter uplift piles and enlarged-base uplift piles. Additionally, the ultimate bearing capacity of uplift piles increases markedly with larger pile diameters and diameter of enlarged bottom. Under the same pile diameter, the ultimate bearing capacity of equal diameter uplift piles is substantially lower than that of enlarged-base uplift piles, with the latter exhibiting a 16.7%-66.7% increase. These findings demonstrate that flexible piezoelectric sensing technology holds promise as a novel solution for the long-term operation and maintenance monitoring of pile foundation anti-floating systems.

The accurate identification of vehicle weight and speed based on road embedded piezoelectric systems (REPS) is a hot topic in the field of dynamic weighing research. An analytical method incorporating loss impedance is proposed in this paper to enable accurate vehicle identification using a REPS. Complementing this framework, a multi-field coupled finite element model (FEM) of the traffic load-road-REPS is developed based on a dual-row sensor array configuration, fully accounting for the actual electromechanical structure of the REPS. A systematic investigation is conducted on how key factors-including vehicle weight, speed, tire contact area, and lateral and longitudinal loading deviations-affect the dynamic and piezoelectric response. Building on these insights, this paper introduces a voltage deviation coefficient and a vehicle load compensation coefficient to correct signal distortions caused by variable contact geometries and positional offsets. By incorporating these coefficients into a bias-corrected identification framework, the proposed method enables simultaneous estimation of vehicle speed and wheel load, reducing the wheel-load identification error to 5.54%, approximately 50% lower than that obtained using the uncompensated axle-load prediction. The research results provide a theoretical foundation for the further development and application of REPS-based weigh-in-motion system.

To address the negative skin friction in pile foundations caused by soil settlement under large-area surcharge loading, this study investigated two foundation treatment methods used in coastal reclamation areas: shallow vacuum preloading (≤ 5 m) and subsequent deep (secondary) vacuum preloading (15–20 m). Field tests on the negative skin friction of a single pile were conducted using two groups of PHC pipe piles in the New Campus Project of Zhejiang Oriental Vocational and Technical College. By monitoring pile and surrounding soil settlement, pore water pressure, pile shaft axial force, and shaft skin friction, the evolution of negative skin friction and the dynamic characteristics of the neutral point were analyzed. The test results show that deep vacuum preloading can significantly reduce pile settlement, surrounding soil settlement, the peak pile shaft axial force, the peak negative skin friction along the pile shaft, and the neutral point depth ratio. Over time, pile settlement, soil settlement, pile shaft axial force, and negative skin friction all increased, whereas the neutral point moved upward and gradually stabilized. Compared with shallow vacuum preloading, deep vacuum preloading reduced the average negative skin friction coefficient along the pile shaft by 30.00

This paper systematically examines the design principles of pile-supported reinforced embankments through comparative analysis with field measurements. Building on engineering practice, we propose an optimized "concentric soil arch" model. Employing limit equilibrium theory and the Mohr-Coulomb criterion, the study analyzes load distribution mechanisms in cohesive-fill embankments, deriving a novel load-sharing ratio formulation. A mechanical model incorporating both interfacial friction and subgrade reaction is developed, assuming parabolic reinforcement deflection within the cushion layer, leading to an enhanced analytical method for tensile membrane effects. The introduction of load coefficient beta quantitatively accounts for reinforcement's influence on soil arching development. The proposed methodology combines soil arching and membrane effects to determine the comprehensive load-sharing ratio. Validation against field data and existing theoretical solutions demonstrates strong agreement, confirming the model's accuracy and providing reliable theoretical guidance for engineering applications.

Filter mudcakes are produced by filtering and dewatering waste slurries from engineering construction and river dredging. The poor mechanical properties of filter mudcakes make them unsuitable for subgrade filling, but converting them into subgrade filling that meets road engineering requirements solves disposal problems. In this work, the performance of modified filter mudcakes (MFMs) was assessed through the optimisation of curing agents, assessment of engineering characteristics and centrifuge modelling. The solidification effect was found to be greatest when 8% ground granulated blast-furnace slag, 4% quicklime and 1% gypsum were added to the filter mudcake. For this mix, the compressive strength was 2730 kPa after 7 days and the water stability coefficient was 85%. The California bearing ratio of these filter mudcakes was 33.7% at 7 days, and the compression coefficient (<0.1 MPa-1) and the permeability coefficient (5.39 x 10(-8 )cm/s) both met the specification requirements at a dosage of 4%. As the degree of compaction was increased from 88% to 97%, the final settlement of the new MFM subgrade at the centre decreased from 50.9 mm to 35.4 mm, and that of the shoulder decreased from 42.3 mm to 29.6 mm, meeting specification requirements (<100 mm). The results support the excellent long-term stability and application potential of MFMs as subgrade materials.

Pile foundations, as a critical foundation technology in modern engineering, are often associated with accidents resulting from their concealed nature and complex geological conditions. Real-time monitoring of axial force allows for tracking stress variations within piles and issuing early warnings, thereby contributing to the optimization of pile foundation design and construction parameters. To address the high costs and sensor vulnerability associated with conventional distributed axial force testing methods, this study employs sensor-enabled piezoelectric geocable (SPGC) in comparison with conventional strain gauges during indoor model testing. This study analyzes the distribution of axial forces within piles and the migration patterns of neutral points under shallow and deep vacuum preloading conditions. Test results indicated that, compared with shallow vacuum preloading treatment, deep vacuum preloading significantly reduced both pile settlement and peak axial force. The peak axial forces monitored by SPGC and strain gauges decreased by 8.4

Soil setup is known to enhance the capacity of jacked piles and is well documented for axial resistance, but its influence on lateral behavior and corresponding evaluation methods remain limited. In this study, a new theoretical framework is proposed to estimate the time-dependent lateral response of closed-ended piles in normally consolidated clay by jointly considering installation-induced disturbance and subsequent consolidation. The framework couples cavity expansion theory with an effective stress approach to capture the evolution of pore pressure, effective stress and strength from installation through reconsolidation, and to quantify the attendant changes in pile–soil interaction. Its performance is demonstrated against finite-element simulations and a field experiment, showing close agreement. Results reveal a strong link between lateral capacity gain and the dissipation of excess pore pressure. Parametric studies further show that rigid piles experience significantly greater capacity improvements than flexible piles, as their associated soil flow mechanisms enable the mobilization of a wider zone of strength-enhanced soil. In addition, increasing pile diameter prolongs the dissipation of excess pore pressure and thus the setup process. While the setup effect for laterally loaded piles is generally less substantial than that widely reported for axially loaded piles, especially for flexible piles, the present framework offers a useful means of evaluating its influence in applications where lateral stiffness and deformation are particularly sensitive and govern performance.

High-density polyethylene (HDPE) pipes, valued for their flexibility and corrosion resistance, are increasingly used in infrastructure, yet their behavior under uneven settlement in soft soil remains underexplored.Uneven settlement directly threatens the safety of buried pipelines. This study investigated the mechanical response of HDPE pipelines in soft soil foundations through a combined approach of model tests and numerical simulation (FLAC3D). The results indicate that, under single-factor conditions, increasing the pipe diameter significantly reduces the peak stress in the pipeline (by up to 44.78% in tests), while its effect on suppressing vertical displacement remains limited. Conversely, increases in burial depth and settlement range exacerbate the bending moment, stress, and displacement responses, leading to more pronounced structural deformation. Unlike single-factor studies, this study conducted a systematic multi-factor coupling analysis, which reveals that under shallow burial conditions(≤1.4 m), using a large diameter (≥480 mm) can effectively control both stress and displacement. For a small settlement range (<2.7 m), pipe diameter plays a dominant role in displacement control, whereas stress rebound may occur for a large settlement range (>5.4 m). The influence of burial depth is more significant within a small settlement range (<3.6 m) but diminishes for a large settlement range (>4.5 m). Based on the numerical results, a multi-factor coupled prediction model for stress and displacement was established using nonlinear surface regression, with a verified prediction error within ±10%. However, its applicability is strictly limited to the geological conditions and parameter ranges studied herein. In practical applications, it must be validated against site-specific conditions and should not be extrapolated to scenarios significantly different from those considered in this study.The findings of this study provide theoretical foundations and practical tools for the preliminary design and selection, monitoring point placement at critical sections, maintenance strategy optimization, safety assessment, and design refinement of HDPE pipes in soft soil regions.

Buried bending deformation and failure are the most critical threats to pipeline structural integrity, making realtime deformation monitoring essential. This study presents a novel monitoring approach using a sensor-enabled piezoelectric geocable (SPGC) to assess buried pipeline bending deformation. Overhead and buried pipeline experiments were conducted under dynamic loading conditions using a dynamic-static test system. Monitoring performance was evaluated using voltage and impedance signals generated by the SPGC. The overhead pipeline tests demonstrated that impedance signals accurately characterize deformation states, with the bending degree exhibiting a proportional relationship with normalized impedance variation. The tensile side provided the most reliable deformation data. For buried pipelines subjected to simulated vehicle loads, fully-loaded vehicles generated voltage signals 2.5 times higher and normalized impedance variations 1.8 times greater than those from empty vehicles at identical speeds. Furthermore, generalized voltage-speed and impedance-strain calculation models were derived through laboratory testing. Unlike conventional strain gauges limited by spatial resolution and power dependence, the SPGC system enables real-time, distributed, and energy-autonomous monitoring of buried pipeline deformation. These findings demonstrate the potential of the SPGC-based monitoring technique for long-term buried pipeline integrity assessment, providing critical deformation data for structural health assessment.

In prestressed concrete structures, due to mechanical and artificial factors, the grouting of the prestressed pipeline is not dense, which seriously affects the durability and safety performance of the structure. Nondestructive monitoring of the health of the grouting of prestressed pipelines has become a key concern in the industry. This study monitored the grouting quality of prestressed pipelines using the electromechanical impedance method. One lead zirconium titanate (PZT) piezoceramic transducer with epoxy resin protective protection, called a smart aggregate, which has the advantages of low cost, high sensitivity, and wide frequency response range, was bonded on the pipeline and prestressed tendons in the pipeline. The experimental procedures simulated five stages during the grouting process, which included empty status, 25%, 50%, and 75% grouting, and full grouting of the prestressed pipeline. Trends in the conductance and susceptance spectrum curves were analyzed. Both the root-mean square deviation (RMSD) and the compactness index (CI) increased with increasing grouting compactness. The experimental results showed that the RMSD increased with increasing grouting density, and with increasing grouting density, the peak frequencies of the curves shifted in the direction of increasing frequency, and the peak values of the curves decreased. Therefore, the electromechanical impedance technique can effectively monitor the grouting quality of prestressed pipelines.

To investigate the effect of PVD installation depth on the efficiency of surcharge preloading for soft ground improvement, centrifuge model tests were conducted based on a typical airport runway project. Four test groups were designed with PVD installation depths of 18, 22, 26, and 30 m. Key indicators, including settlement, porewater pressure, water content, and undrained shear strength, were monitored to systematically analyze the influence of PVD depth variation on soil consolidation behavior. The results showed that with each 4 m increase in PVD depth, the settlement increment was 10.39 %, 4.44 %, and 0.81 %, respectively. When the installation depth exceeded 22 m, the improvement effect tended to plateau. Therefore, under the conditions of this project, the reasonable installation depth of PVDs lies within the range of 18-22 m, while the precise optimal depth still requires further investigation. Based on one-dimensional and multidimensional consolidation theories, this study proposed a settlement prediction method that converts multi-stage surcharge into an equivalent single-stage load through stress-time integration correction. The predicted results agreed well with the experimental data, with errors in shallow and deep settlement controlled within 5.3 % and 11.6 %, respectively, both within the acceptable range for engineering applications.

The determination and prediction of cyclic shear dynamic strength in over consolidated clay foundations are crucial for the design of the horizontal bearing capacity of pile foundations. This paper conducts a series of undrained cyclic simple shear tests on remolded Wenzhou clay under various conditions of over consolidation ratio, vertical pressure and cyclic stress ratio. Combined with experimental data from four other clays, it is found that the dynamic shear strain and excess pore water pressure of over consolidated clay vary widely under cyclic shear. Hence, it is impossible to set a unified threshold for dynamic strength assessment. The occurrence sequence of four dynamic failure indicators is revealed as follows: the inflection point of the double-amplitude dynamic shear strain curve, the inflection point of the excess pore water pressure curve, the contact between the failure line and the stress path, and the attenuation of the shear stress amplitude. The differences between these occurrences become more pronounced with larger over consolidation ratio, lower vertical pressure or higher cyclic stress ratio. It is proposed that the derivative of double-amplitude dynamic shear strain curve reaching 30

Sensor-enabled piezoelectric geocables (SPGCs) are used for strain and vibration monitoring of various infrastructures structures. However, as a distributed sensor, the influence of temperature on the monitoring signal of SPGCs is inevitable. This study tested the impedance change of SPGCs in static temperature-varying tests and carried out dynamic tensile tests at different temperatures. The static temperature-varying tests showed that, at temperatures ranging from -10 degrees C to 50 degrees C, the SPGC normalized impedance change value increased with increasing temperature. At temperatures ranging from -10 degrees C to 20 degrees C and 20 degrees C-50 degrees C, the normalized impedance change value and temperature were exponentially and linearly related, respectively. Dynamic tensile tests showed that the SPGC tensile strength and yield strain decreased with increasing temperature. With increasing temperature, the SPGC voltage waveform and value changed less, while the impedance response became more sensitive. Therefore, a nonlinear calibration model of the SPGC impedance-strain effect considering the temperature effect was proposed, which can be used for strain calculation under different field ambient temperatures. The test results revealed the influence of temperature on the mechanical and monitoring performance of SPGC, providing support for further engineering applications of this technology.

Traditional vacuum preloading, electroosmotic techniques face challenges such as poor removal efficiency, reinforcement and high energy consumption when treating contaminated sludge with high water content. This study investigates the reinforcement and remediation of nickel (Ni)-contaminated sludge with high water content using an approach combining grouting, vacuum preloading, and electroosmosis (GVE). Through laboratory model tests, the effects of grouting agents, vacuum preloading, and voltage loading modes on Ni removal efficiency, soil reinforcement, and energy consumption were evaluated. The results demonstrate that the grouting of sodium alginate can chelate Ni2+ in the soil, facilitating the removal of heavy metal ions during the electroosmosis process. The GVE combined with vacuum preloading significantly enhances Ni removal rates, achieving up to 94.52 % compared to 65.11 % with electroosmosis alone. Additionally, GVE reduced soil water content to 30.34 % and increased shear strength to 98 kPa, indicating improved soil reinforcement. The step loading further reduced energy consumption by over 35 % compared to constant voltage loading while enhancing both soil remediation and reinforcement. This study concludes that GVE, particularly with step loading and intermittent loading, is an effective and energy-efficient method for remediating and reinforcing heavy metal contaminated sludge.

To study the dynamic seismic responses of buried socketed high-density polyethylene (HDPE) pipes in sandy soil foundations during seismic excitations, pipe acceleration, pipe strain and displacement response data were obtained via indoor scaling tests and FLAC3D numerical simulations to establish a socketed HDPE pipe model. The numerical simulation results were compared with the experimental data to validate the effectiveness of the model. A large-diameter HDPE pipe model was established to simulate actual engineering situations. The difference in the seismic liquefaction response between socketed pipes and nonsocketed pipes was systematically analysed. The mechanical responses of socketed pipes were determined via numerical simulations. Compared with those of straight pipes, the acceleration response and strain of socketed HDPE pipes undergo greater changes, whereas the displacement of straight pipes is greater. The peak strain of the socketed pipe decreases axially from the centre to the ends, with the maximum strain occurring at the pipe centre and the minimum strain occurring at the pipe ends, and the peak strain in the middle of the pipe is more than 4 times greater than that at the ends of the pipe. The peak acceleration of the socketed pipes and its range both increase with increases in the input acceleration peak. The displacement of the socketed pipes increases with increases in the input acceleration peak and the depth of the pipeline, and it decreases with increases in the relative density of the soil body and the diameter of the pipe. In the numerical analysis, different diameters were simulated many times, and an equation for the axial strain and displacement of a pipeline with changes in the pipeline diameter is proposed. At a given burial depth, the socketed pipe strain decreases with increasing pipe diameter, whereas the pipeline displacement increases. For a given pipe diameter, both the strain and displacement of a socketed pipe increase with increasing burial depth.