Soils and FoundationsPub Date : 2025-12-01Epub Date: 2025-09-27DOI: 10.1016/j.sandf.2025.101698
Ankur Abhishek , Anasua GuhaRay , Toshiro Hata
{"title":"Enhanced microstructural analysis of black cotton soil stabilized through rice husk ash integration","authors":"Ankur Abhishek , Anasua GuhaRay , Toshiro Hata","doi":"10.1016/j.sandf.2025.101698","DOIUrl":"10.1016/j.sandf.2025.101698","url":null,"abstract":"<div><div>Black cotton soil (BCS) poses significant complexities in geotechnical applications due to its swelling and shrinkage behavior. It causes significant economic losses globally due to reconstruction and rehabilitation efforts. Reliable soil reinforcement techniques are, therefore, essential to mitigate the deleterious effects of expansive BCS and to ensure the long-term stability of the structures built upon them. The present study explores the application of rice husk ash (RHA) to BCS using nitrogen (N<sub>2</sub>) gas adsorption techniques such as Brunauer–Emmett–Teller (BET), Langmuir, and adsorption isotherm analyses. These techniques are based on the principle that N<sub>2</sub> gas is adsorbed onto the reactive surface sites. The surface of BCS is considered reactive due to its high clay content and the presence of montmorillonite. With the addition of RHA, pozzolanic reactions progress, leading to the development of cementitious phases such as calcium silicate hydrate (C-S-H), which gradually fill these reactive surface sites, leading to a decrease in the material’s gas adsorption capacity. This reduction in N<sub>2</sub> gas adsorption provides a measurable indication of pozzolanic activity, allowing for a more detailed microstructural assessment of stabilized soil systems. A sharp reduction in N<sub>2</sub> gas adsorption was observed in BET, Langmuir, and adsorption isotherm analyses at 6 % RHA content, conducted on 28-day cured Unconfined compressive strength (UCS)-tested samples. BET results showed a reduction in adsorption from 0.0635 mg/g for untreated BCS to 0.0385 mg/g at 6 % RHA concentration. This 6 % RHA content also corresponds with peak mechanical performance observed in UCS, California bearing ratio (CBR), indirect tensile strength (ITS), and cone penetration test (CPT), highlighting a strong correlation between microstructural improvement and engineering behavior. The UCS of untreated BCS (183 kPa) increased to a maximum of 819 kPa after 7 days and 1370 kPa after 28 days of curing, confirming 6 % RHA as the optimum dosage.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101698"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Interface clogging between soil and attenuation layer of embankment based on LBM-DEM coupled numerical method","authors":"Xudong Zhang, Atsushi Takai, Tomohiro Kato, Takeshi Katsumi","doi":"10.1016/j.sandf.2025.101697","DOIUrl":"10.1016/j.sandf.2025.101697","url":null,"abstract":"<div><div>The reuse of excavated soil is a popular topic all around the world. To decrease the contaminants in excavated soil influencing the ground, an attenuation layer is generally used to absorb these contaminants and isolate the excavated soil and ground. The drainage clogging problem that is sometimes generated has attracted much attention in embankment engineering. The attenuation layer drainage effect is not only related to the loading capacity of the ground, but also to the soil properties. Thus, it is significant to clarify the mechanism of drainage clogging. As the micro monitoring of clogging is still difficult to achieve, a numerical simulation method is used in the present study to elaborate this mechanism. Based on the coupled lattice Boltzmann method (LBM) and discrete element method (DEM), the drainage clogging phenomenon during the filtering process is simulated from a micro perspective. The results indicate that particles can form an arch structure and lead to clogging above the pore of the attenuation layer. The formation of such a clogging arch structure prevents the discharge of soil particles and greatly decreases the fluid velocity, approximately 2.7 and 9.3 times for the two types of soil used in this study, namely, Soil A and Soil B, respectively. It is noted that the fluid velocity, rather than impermeability, remains a basic value. The velocity distribution around the pore of the attenuation layer has a certain shape depending on the velocity of the LBM cells. The size of this distribution regularly changes with the distance to the attenuation layer pore. In addition, knowledge of the soil skeleton is necessary for analyzing the arch-forming process in polydisperse particle systems. The larger particles (0.043–0.085 cm) are closely related to the formation of the soil skeleton, whereas the finer particles are related to the filling and stabilization of the soil skeleton. The clog stabilization of the soil particles in these two samples is mainly controlled by the average normal forces (1.87 × 10<sup>−6</sup> N and 1.20 × 10<sup>−6</sup> N, respectively) according to the variation in forces during the clogging process. Based on the analysis, an explanation of the clogging process is proposed in this study from a microscopic perspective, providing a better description of the soil skeleton clogging theory under embankment drainage.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101697"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-12-01Epub Date: 2025-10-10DOI: 10.1016/j.sandf.2025.101702
Sohail Ahmad , Tianbo Peng , Muhammad Salman Khan
{"title":"Numerical and experimental study on the seismic performance of caisson foundations","authors":"Sohail Ahmad , Tianbo Peng , Muhammad Salman Khan","doi":"10.1016/j.sandf.2025.101702","DOIUrl":"10.1016/j.sandf.2025.101702","url":null,"abstract":"<div><div>Caisson foundations are widely used in long-span bridges for their superior load-bearing capacity and stability, yet their seismic behavior remains inadequately understood. Current seismic design approaches often neglect soil-caisson dynamic interaction (SCDI), leading to inconsistencies between theoretical models and actual responses. This study investigates the seismic response of caisson foundations through large-scale shaking table tests and finite element simulations in Abaqus, validated using experimental results from the Taizhou Yangtze River Highway Bridge. The findings indicate that the presence of caisson foundations has minimal impact on the fundamental frequency of the soil, while an increase in bridge tower mass reduces the system’s first-order frequency, altering its dynamic characteristics. Specifically, a 21 % reduction in the first-order frequency was observed when the tower mass increased from 230 kg to 370 kg. Additionally, acceleration responses at the tower top differed by less than 6 % when using the Clough hyperbolic contact model compared to experimental results, demonstrating strong agreement. The results also show that caisson foundations primarily undergo rigid body motion under seismic excitation, with negligible deformation. Furthermore, the Clough hyperbolic constitutive model accurately captures nonlinear contact behavior at the soil-caisson interface, providing better agreement with experimental observations under high-intensity seismic loading. This study highlights the importance of incorporating realistic SCDI effects in seismic design and suggests that enhanced numerical modeling techniques can improve the reliability of seismic performance predictions for long-span bridges with caisson foundations. These insights contribute to the development of more resilient seismic design strategies, reducing structural vulnerabilities in seismic-prone regions.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101702"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Large-area slope stability analysis: Performance comparison of three-dimensional limit equilibrium methods","authors":"Daichi Sugo , John Y. Choe , Saneiki Fujita , Nilo Lemuel J. Dolojan , Kenta Tozato , Reika Nomura , Kenjiro Terada , Eiji Tominaga , Shoji Iwanaga , Shuji Moriguchi","doi":"10.1016/j.sandf.2025.101703","DOIUrl":"10.1016/j.sandf.2025.101703","url":null,"abstract":"<div><div>3D limit equilibrium methods (LEMs) for assessing slope stability over large areas have been applied in some studies (e.g., <span><span>Tran et al., 2018</span></span>; He et al., 2018). However, their use remains limited compared to computationally cheaper alternatives (e.g., statistical or simple physics-based models) due to higher computational demands and the fact that their practical accuracy has not been sufficiently examined. In addition, while the Hovland method is recognized as the most computationally efficient 3D LEM, its accuracy has been questioned (e.g., Azzouz and Baligh (1978); Hutchinson and Sarma (1985)), which has further hindered the broader adoption of 3D LEMs. This study compares three well-established 3D LEMs. It first compares the characteristics of these methods under simple slope conditions. Then, the comparison is extended to a large area with numerous slopes, considering actual terrain data and a heavy rainfall event. The findings reveal variations in factor-of-safety values across methods. However, receiver operating characteristic curve indicated no significant differences between their accuracies in predicting the actual landslide distribution. This suggests that the Hovland method, boasting the lowest computational cost (e.g., under 50 min) among the methods, can effectively pinpoint high-risk areas identified by the other methods (e.g., over 7 h) by simply adjusting the factor-of-safety threshold. To further generalize these findings, future work should additionally consider highly variable and complex inputs, such as the spatial distribution of groundwater tables.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101703"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-12-01Epub Date: 2025-09-27DOI: 10.1016/j.sandf.2025.101699
Maliha Tasnim Tilat, Sascha Henke
{"title":"Dynamic analysis of wave propagation due to pile installation using numerical simulations","authors":"Maliha Tasnim Tilat, Sascha Henke","doi":"10.1016/j.sandf.2025.101699","DOIUrl":"10.1016/j.sandf.2025.101699","url":null,"abstract":"<div><div>This paper discusses the results of a preliminary study of numerical simulations investigating wave propagation during the installation of in-situ driven concrete piles (type Franki pile). Franki piles are cast-in-situ piles that are installed by driving a steel casing into the ground using heavy ramming of a cylindrical hammer. It is a dynamic pile installation process where the hammer directly transfers the dynamic forces to the soil within the installation tube causing high wave propagation through the soil. When installed in groups, the vibrations caused by the driving process of one pile may result in damages to the early-age concrete of adjacent piles. The dynamic response of a pile during driving is very complex, involving the interactions of hammer, pile, and soil during the impact. Such complex soil-structure interaction problems can be represented numerically by modeling the pile installation process using realistic parameters (ground conditions, ramming energy etc.). As a preliminary study, a single pile installation is simulated using the FEM software Abaqus. The simulation is based on a Coupled Eulerian-Lagrangian (CEL) approach where the soil is modeled using the hypoplastic constitutive model. The aim is to investigate parts of the installation process regarding the effect of discrete hammer drops. Within the CEL method, the pile hammer is modeled as a Lagrangian part, while the soil is treated as a Eulerian part. As a result of the simulations, a realistic amplitude pattern can be observed. This study serves as the basis for the subsequent phase, wherein a newly installed neighboring pile is introduced alongside the pre-existing pile. In this context, the influence of the adjacent pile on the wave propagation due to the neighboring pile is evaluated.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101699"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-12-01Epub Date: 2025-10-30DOI: 10.1016/j.sandf.2025.101705
João Batista de Oliveira Libório Dourado , Lijun Deng
{"title":"Field investigation of steel screw micropiles under axial loads in cohesionless and cohesive soils","authors":"João Batista de Oliveira Libório Dourado , Lijun Deng","doi":"10.1016/j.sandf.2025.101705","DOIUrl":"10.1016/j.sandf.2025.101705","url":null,"abstract":"<div><div>Steel screw micropiles are a new pile type for light load applications or building remediation, offering several advantages over conventional concrete piles. Unique feature of screw micropile shafts requires distinctive design approaches; despite the growing use, there is limited field measured data on their axial failure or torque-based design. This study aims to evaluate the ultimate capacity of screw micropiles, analyze the axial failure mode, develop empirical correlations between installation torque and ultimate capacity, and refine a torque estimation method based on Cone Penetration Tests (CPT). Full-scale axial compression tests in both cohesionless and cohesive soils were performed on five screw micropile types with diameters ranging from 76 mm to 114 mm and lengths from 1.6 m to 3.0 m. Each test was repeated three times, totalling 30 tests. In-situ and laboratory investigations were conducted to characterize the soils. Results showed that in cohesionless soil, installation torque increased linearly with depth; while in cohesive soil, torque tended to stabilize after the threaded segment was fully embedded. The evidence suggests the impact of soil strength and disturbance on installation torque. A reliable linear relationship was observed between installation torque and ultimate capacities, with torque factors (defined as the ratio of pile ultimate capacity to max installation torque) ranging from 21.5 to 27.8 m<sup>−1</sup>. Back-analysis suggested that the axial failure is governed by local bearing beneath each thread. The CPT-based torque estimation method in previous studies for piles in cohesive soil was revised to include the effect of smooth segment, and the revised method suggested consistent comparison with the measured torque.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101705"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145417144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-12-01Epub Date: 2025-09-18DOI: 10.1016/j.sandf.2025.101685
Zhiliang Wang , Jiangpeng Cai , Miao Li , Linfang Shen
{"title":"Upcycling rice husk biowaste to improve cement-based peat soil stabilization","authors":"Zhiliang Wang , Jiangpeng Cai , Miao Li , Linfang Shen","doi":"10.1016/j.sandf.2025.101685","DOIUrl":"10.1016/j.sandf.2025.101685","url":null,"abstract":"<div><div>Traditional stabilizers, such as kaolin and sodium bentonite, introduce complications when applied to cement-based peat soil stabilization. This study explores biowaste stabilizers – rice husk ash (RHA) as a pozzolan material and rice husk fiber (RHF) as reinforcing – as a sustainable and practical alternative. A three-stage experimental strategy was designed to identify the optimal stabilization method. Stage 1 determined the ideal RHA particle size and content without RHF. Stage 2 incorporated RHF to assess its best pretreatment method and optimal dosage; Stage 3 investigated the stabilization mechanisms. A series of physical and mechanical experiments confirmed that RHA and RHF improved cement-based peat soil stabilization. RHA played a primary role as a pozzolanic material, while RHF is secondary as reinforcement. Unconfined compressive strength (UCS) increased by 146.6 % with RHA alone and by 202.1 % with both RHA and RHF compared to cement only. This is achieved by using fine RHA particles and Ca(OH)<sub>2</sub>-treated RHF. The content for both RHA and RHF is critical, especially noting that the optimal content of RHA varies as the cement content varies. Microscopic analysis confirmed that RHA enhanced pozzolanic reaction, producing more cementitious products (C-S-H) that filled pores and bonded soil particles. Additionally, a significant quantity of cementitious products formed on the coarse surface of pre-treated RHF, reinforcing soil-fiber bonding. Stabilizing 1 m<sup>3</sup> of peat soil by upcycling biowaste reduces carbon emissions by 61.9 % and costs by 25.8 % compared to using cement only. This study demonstrates that upcycling biowaste provides an effective, sustainable, economical, and easy-to-implement solution for improving cement-based peat soil stabilization.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 6","pages":"Article 101685"},"PeriodicalIF":3.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145108726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-09-01Epub Date: 2025-08-12DOI: 10.1016/j.sandf.2025.101659
Osamu Otsuka , Mitsuo Yamashita
{"title":"Bioremediation for seleno-oxyanions in tunnel-excavated muck using selenate-reducing bacterium Stutzerimonas stutzeri NT-I","authors":"Osamu Otsuka , Mitsuo Yamashita","doi":"10.1016/j.sandf.2025.101659","DOIUrl":"10.1016/j.sandf.2025.101659","url":null,"abstract":"<div><div>Selenium is a rare metal found mainly in volcanic sediments; it is naturally distributed in Japan owing to its sulfide deposits. Selenium exists in soil as highly toxic and soluble seleno-oxyanions, namely, selenate and selenite. The Japanese government has established standards for soluble selenium concentrations in soil, achieved by water shielding or the addition of insolubilization agents. If the selenium (and/or other heavy metals) in tunnel-excavated muck exceeds the environmental standards, it should be treated similarly to contaminated soil. However, conventional treatments leave selenium residues in tunnel-excavated muck, preventing their reuse due to the risk of selenium re-elution. This study attempted to insolubilize soluble seleno-oxyanions in tunnel-excavated muck by adding the bacterium <em>Stutzerimonas stutzeri</em> NT-I, which reduces selenate to insoluble elemental selenium and then to volatile dimethyl diselenide. Selenate reduction tests were conducted by adding heavy metals, including As(III), As(V), Cd(II), Pb(II), and Fe(III), to examine the selenate reduction ability and growth of <em>S. stutzeri</em> NT-I in the presence of their ions. The results showed that the <em>S. stutzeri</em> NT-I reduced the selenate by 50 mg/L concentrations for all the tested contaminants. In naturally contaminated tunnel-excavated muck, heavy metal elements, nitrate, and nitrite contents were detected at levels of <50 mg/L, suggesting that they do not adversely affect the selenate reduction by <em>S</em>. <em>stutzeri</em> NT-I. The results indicate that selenium insolubilization using <em>S</em>. <em>stutzeri</em> NT-I can be applied to a wide range of tunnel-excavated muck.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 5","pages":"Article 101659"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-09-01Epub Date: 2025-08-26DOI: 10.1016/j.sandf.2025.101681
Yao Xiao , Qiuyan Lin , Wenyue Fang , Rui Zhang
{"title":"Seismic bearing capacity of strip footing above cavities in rock masses","authors":"Yao Xiao , Qiuyan Lin , Wenyue Fang , Rui Zhang","doi":"10.1016/j.sandf.2025.101681","DOIUrl":"10.1016/j.sandf.2025.101681","url":null,"abstract":"<div><div>This paper employs an adaptive finite element limit analysis (AFELA) combined with nonlinear programming (NLP) to investigate the seismic bearing capacity of strip footings overlying cavities in rock masses that obey the generalized Hoek–Brown (GHB) failure criterion. The feasible arc interior point algorithm (FAIPA) is utilized to solve the optimization models, and a novel imprecise step search algorithm is introduced to improve the NLP convergence. Based on the self-developed AFELA procedure, the bearing capacity reduction factor <em>R</em> of strip footing on a rock mass has been calculated, with the results presented in tables and charts. Parametric analysis reveals that a footing centered above a cavity does not exhibit the lowest capacity, likely due to a beneficial arching effect. Failure modes associated with varying parameters are also discussed, and the results show that increasing the horizontal seismic coefficient reduces the extent of the failure zone.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 5","pages":"Article 101681"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144904645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soils and FoundationsPub Date : 2025-09-01Epub Date: 2025-08-26DOI: 10.1016/j.sandf.2025.101675
Bin Zhuo, Yong Fang, Liupan Dou, Xuedan Liu, Muyuan Zhu, Xiongyu Hu
{"title":"An experimental and theoretical research on shield screw conveyor discharging efficiency in moderately weathered mudstone strata and its influence on clogging","authors":"Bin Zhuo, Yong Fang, Liupan Dou, Xuedan Liu, Muyuan Zhu, Xiongyu Hu","doi":"10.1016/j.sandf.2025.101675","DOIUrl":"10.1016/j.sandf.2025.101675","url":null,"abstract":"<div><div>When an earth pressure balance shield machine is tunneling in cohesive soils, a poorly effective soil conditioning scheme often leads to clogging in the cutterhead and the screw conveyor, which reduces tunneling efficiency and may even cause the shield machine to stop tunneling. Different from the conventional test method that use artificial clay soil, this study relies on the field shield engineering in mudstone strata and conducts soil conditioning tests using the field soil as the basic material. Using a shield soil migration model test, the whole process of clogging in a screw conveyor is reproduced, and the pattern of migration change of soil in the screw conveyor is obtained. The screw conveyor torque decreases with the increase of foam injection rate. When the slump of soil reaches 15 cm, the torque tends to be stable. Based on this, this study innovatively establishes a theoretical calculation model that can quantitatively describe the relationship between the soil discharge and the pressure gradient. Experimental verification shows that this model can not only quantitatively describe the variation laws of the soil discharge and the pressure gradient, but also qualitatively reveal the influence mechanism of the soil chamber pressure and soil fluidity on the discharge efficiency. Finally, using the Ziyang line of the Chengdu rail transit as a field test, it is found that under the recommended soil conditioning scheme, the clogging problem in the shield cutterhead and screw conveyor is greatly reduced and the efficiency of shield tunneling is significantly improved.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 5","pages":"Article 101675"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}