Xiaoyu Yang

The classical one-dimensional electroosmotic consolidation theory assumes a linear potential distribution independent of time, thereby neglecting the influence of spatiotemporal evolution of soil electrical properties on the consolidation process. To address this limitation, a one-dimensional electroosmotic model test is conducted in this study, revealing the spatiotemporal evolution characteristics of the electric potential field. The results indicate that changes in electrode-soil interfacial properties and the nonuniform evolution of soil electrical parameters are the primary factors responsible for the redistribution of the potential field. On this basis, the Physics-Informed Neural Networks (PINNs) method is introduced for potential field reconstruction, fully leveraging the combination of physical constraints and data-driven approaches to achieve spatial densification of the potential field under sparse observations. Furthermore, a surrogate model characterizing the spatiotemporal evolution of the potential field is constructed and embedded into the governing equation of electroosmotic consolidation as a nonhomogeneous source term, which is then solved numerically using the finite difference method. The computational results demonstrate that the negative excess pore water pressures obtained by the proposed method exhibit smaller magnitudes than those predicted by the classical theory, with the discrepancies primarily concentrated near the anode, reaching a maximum of approximately 120 kPa. The proposed approach provides a feasible pathway for electroosmotic consolidation analysis that accounts for the spatiotemporal evolution of the electric potential field.

The issue of water-enriched surrounding rock induced by excavation disturbances in loess tunnels represents a significant challenge for the construction of loess tunnel projects. Based on the concepts of lime sac water absorption, expansion, and compaction, consolidation, and drainage of surrounding rock and soil, as well as active reinforcement, a tandem water-absorbing and compaction anchor with heat-expansion and compaction consolidation functionality has been developed. To facilitate the engineering design and application of this novel anchor, a consolidation equation for cylindrical heat source-consolidated soil was derived under conditions of equal strain and continuous seepage. Considering the impact of temperature in the thermal consolidation zone on soil permeability, an analytical solution for the average degree of consolidation of the surrounding soil after support with the water-absorbing and compaction anchor was provided. The correctness of the solution was verified through engineering examples, demonstrating the reasonableness of the theoretical calculation method used in this study.

The attenuation of effective potential is a significant factor leading to the low postdrainage efficiency in the electroosmotic consolidation and drainage methods. In this study, the influence of the attenuation of effective potential on the electroosmotic consolidation process and the problem of solving the governing equations were investigated. A 102.5‐hr one‐dimensional electroosmotic consolidation test was performed to monitor the changes in the properties of the soil interior and the soil–electrode interface, and the variation curve of the effective potential in the test model was measured. The time‐dependent nature of the potential distribution due to the attenuation of effective potential contradicts the assumption of introducing intermediate variables. To address this key issue, the variation curve of the effective potential was linearly segmented, ensuring the validity of introducing intermediate variables within each local state segment. Based on the continuity between state segments, the initial conditions of the governing equations in different state segments were updated, thereby extending the differential iteration within local state segments to the entire electroosmotic time domain. A finite‐difference program for this method was developed using the Python language. Calculations and analyses based on the measured potential data were performed, revealing that a decrease in potential leads to a reduction in the effectiveness of electroosmotic drainage and consolidation in terms of the instantaneous distribution of pore pressure and the overall average degree of consolidation. This method can reflect the influence of the attenuation of effective potential on the pore water pressure during the electroosmotic consolidation process. The research findings of this paper can provide theoretical and numerical support for the improvement and engineering application of the electroosmotic consolidation and drainage method.

To study the effect of the lime‐soil compaction pile on the collapsible loess foundation and the influence of water‐heat‐force characteristics on the soil during compaction, the field test of lime‐soil compaction pile treatment of collapsible loess foundation is carried out. This paper monitors the process of soil temperature, water, and soil pressure change in the process of pile forming. According to the macroprocess and micromechanism of lime‐soil compaction pile treatment of collapsible loess foundation, the qualitative law of water‐heat‐force change in the process of pile forming is obtained. Meanwhile, the influence of soil damage is introduced in the process of compaction expansion. The model of pore expansion under linear damage conditions in the plastic zone is established. The formula of radial stress distribution under damage conditions is given. The influence of different damage factors on the expansion process is analyzed.

Extremely broken phyllite is widely distributed and is easily seen in engineering construction. Aiming at the problem that the empirical strength parameters of extremely broken surrounding rock have intense subjectivity and significant difference, based on the characteristics of the existence of particle group state in the highly broken surrounding rock, the fractal theory and large‐scale direct shear test are used, the fractal description of polar broken phyllite samples with different pile numbers in fault fracture zone of Qinyu Tunnel is carried out, and the fractal dimensions and empirical strength parameters of each sample are determined. Based on a fractal description and large shear test, the functional relationship between fractal dimension and empirical strength parameter of extremely broken phyllite in fault fracture zone is established, and the quantitative value method of empirical strength parameter determined by fractal dimension of extremely broken phyllite is given, which provides ideas for the quantitative value of empirical strength parameter of the similar extremely broken surrounding rock.

In the electroosmosis method, when the distance between the opposite electrode and the same electrode is equal, the two‐dimensional effect of electroosmotic consolidation is significant, and the use of one‐dimensional model will overestimate the potential gradient, making the calculated pore pressure value too large. Aiming at this problem, according to the electrode arrangement rule and the minimum composition, a punctiform electrode unit model is proposed, and electroosmotic experiments are carried out on the symmetric and asymmetric unit models. The two‐dimensional electroosmotic consolidation governing equation of the punctiform electrode unit is established. The electric potential field of the electrode unit and the finite element form of the electroosmotic consolidation equation are given by the Galerkin method. The PyEcFem finite‐element numerical library is developed using Python programming to calculate. The research results show the following: (1) The two‐dimensional effect of the potential field distribution of the punctiform electrode unit is significant. The reduction of spacing of the same nature electrode in the symmetrical unit can make the potential distribution close to a uniform electric field. The asymmetry prevents the electric potential field distribution from being reduced to a one‐dimensional model. (2) The number of anodes will affect the electroosmosis effect of the soil. The more the anodes, the better the electroosmosis reinforcement effect of the soil, and the distribution of negative excess pore water pressure will be more uniform. (3) In the early stage of electroosmosis, the more the drainage boundaries, the faster the generation of negative pore pressure, but in the middle and late stages of electroosmosis, the potential value becomes the decisive factor, and the amplitude of negative pore water pressure in asymmetric units is higher than that in symmetric units. The potential distribution will not affect the degree of consolidation but will affect the extreme pore water pressure.