Tensile cracks play a pivotal role in the formation and evolution of reservoir landslides. To investigate how tensile cracks affect the deformation and failure mechanism of reservoir landslides, a novel artificial tension cracking device based on magnetic suction was designed to establish a physical model of landslides and record the process of landslide deformation and damage by multifield monitoring. Two scenarios were analyzed: crack closure and crack development. The results indicate that under crack closure, secondary cracks still form, leading to retrogressive damage. In contrast, under crack development conditions, the failure mode changes to composite failure with overall displacement. The release of tensile stresses and compression of the rear soil are the main driving forces for this movement. Hydraulic erosion also plays a secondary role in changing landslide morphology. The results of multifield monitoring reveal the effects of tensile cracking on reservoir landslides from multiple perspectives and provide new insights into the mechanism of landslide tensile-shear coupled damage.

A novel slope stabilization technique was recently developed incorporating screw piles with vegetated flapped soilbags. These screw piles are subjected to lateral stress from soil slope and their deformation can be difficult to quantify, given the fluctuating pore-water pressure and heterogeneous soil conditions. This study proposes the use of in-situ spectral analysis of surface waves (SASW) test to estimate the small-strain soil stiffness which can then be factored to calculate the lateral deformation of the pile in finite element modelling based on prescribed pore-water pressure change. A case of bioengineered slope in Kanchanaburi province, Western Thailand was studied, involving field monitoring of pile head tilt, pore-water pressure, suction, and soil moisture over one year. The findings revealed pile head tilt of up to 0.2 degrees in response to rainfall and rise in pore-water pressure and soil moisture over one year period. A series of finite element modelling were performed using factored shear moduli from in-situ SASW test and the monitored pore-water pressure variation to reproduce the amount of pile head tilting as observed in the field during one year. It was revealed that by assuming operational shear modulus ranging between 0.0075 and 0.01 times small-strain soil stiffness, a satisfactory agreement was obtained between field measurement and analysis of pile movement. This findings provides a basis for further studies on performance of bioengineered slope utilizing screw piles. (c) 2025 Japanese Geotechnical Society. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Rainwater infiltration will significantly increase the pore water pressure of shallow soil, thus reducing the stability of slope soil. In order to study the migration law of rainwater infiltration wetting front of vegetated slopes, the law of rainfall infiltration was analyzed by using the data of in field monitoring test of slopes. Meanwhile, a vegetated slope infiltration model was established, and the changes in the pore pressure and saturation of the idealized root system on the slope under different rainfall were investigated and analyzed. We found that medium to heavy rainfall (>10 mm/d) can change the shallow water content of vegetated slopes, and light rainfall cannot change the water content; the change in water content of vegetated slopes is less than that of unvegetated slopes under long-duration rainfall, and more than that of unvegetated slopes under short duration rainfall; the change in water content of Ligustrum quihoui Carr. L. shrub slopes are smaller than that of Nerium oleander L. shrub slopes, which has a better effect of slope; under short duration rainfall, the permeability coefficient of root consolidation zone of the vegetated slope is large, the rainwater infiltration speed is fast and it is not easy to cause shallow landslides; with the increase of rainfall time, the plant root system provides a good pore channel, the depth of sudden change of pore pressure of vegetated slope is smaller than that of unvegetated slope. The results of this study provide a reference and analytical basis for vegetated slopes of road graben under rainfall.

Freeze-thaw (F-T) cycles are a primary contributor of pavement damages in seasonal frost regions. Geosynthetics stabilization has been a promising solution for enhancing the roadways performance in cold regions. However, in comparison with the practical applications, research on the geosynthetics stabilization in cold-region roads is scarce and its efficacy is yet to be quantified. This study presents the full-scale test on geosynthetics-stabilized sections in a flexible pavement in Sturgeon County, Alberta. It focused on the investigation of three separate test sections with bases stabilized by two types of geocells and one geogrid composite, each fully instrumented with earth pressure cells, thermocouples, and moisture sensors. This experimental program consisted of plate loading tests and trafficking tests on each test before and after the first F-T season, and monitoring of soil temperatures, moisture contents, and loads transferred to subbases while the sections were open to general traffic. The results showed seasonal F-T cycles resulted in increased pavement settlement, decreased load transfer ratio, and increased stress distribution angle under the plate loading. The traffic-induced stress on the subbases increased during the spring thaw but decreased afterwards.

The issue of geotechnical hazards induced by excavation in soft soil areas has become increasingly prominent. However, the retaining structure and surface settlement deformation induced by the creep of soft soil and spatial effect of the excavation sequence are not fully considered where only elastic-plastic deformation is used in design. To understand the spatiotemporal effects of excavation-induced deformation in soft soil pits, a case study was performed with the Huaxi Park Station of the Suzhou Metro Line S1, Jiangsu Province, China, as an example. Field monitoring was conducted, and a three-dimensional numerical model was developed, taking into account the creep characteristics of mucky clay and spatiotemporal response of retaining structures induced by excavations. The spatiotemporal effects in retaining structures and ground settlement during excavation processes were analyzed. The results show that as the excavation depth increased, the horizontal displacement of the diaphragm walls increased linearly and tended to exhibit abrupt changes when approaching the bottom of the pit. The maximum horizontal displacement of the wall at the west end well was close to 70 mm, and the maximum displacement of the wall at the standard reached approximately 80 mm. The ground settlement on both pit sides showed a trough distribution pattern, peaking at about 12 m from the pit edge, with a settlement rate of -1.9 mm/m per meter of excavation depth. The excavation process directly led to the lateral deformation of the diaphragm walls, resulting in ground settlement, which prominently reflected the time-dependent deformation characteristics of mucky soft soil during the excavation process. These findings provide critical insights for similar deep excavation projects in mucky soft soil, particularly regarding excavation-induced deformations, by providing guidance on design standards and monitoring strategies for similar geological conditions.

Seepage flow through complex foundations is one of the main factors causing dam failure. To foresee this problem, seepage modeling and analysis are usually performed. This study investigated seepage behavior as affected by complex, foliated, rock foundations in an earth dam. The PLAXIS 3-D LE software was used to analyze seepage problems for steady state flow. The normal high-water level (NHWL) with anisotropic permeability was considered in the models. The anisotropic permeability of foliated rocks was determined according to the angle of inclination. The flow characteristics along the dam axis could be divided into five zones, with three zones for the middle parts (MD1, MD2 and MD3) and one zones for each of the two abutments (LA and RA). The quantities of flow (water transmissibility) upstream to downstream (QX) on each zone highly depended on the geological structures. Although the average seepage transmissibility values of the residual soil and phyllite were almost equal for every zone. The values in the anticline areas were higher than for the syncline areas, especially for the middle zones. The flow tended to transfer from residual soil into phyllite rock in the anticline area. The transmissibility ratio of anticline to syncline was more than 2 times for both the residual soil and phyllite. The finger drain and river channel attracted substantial flow in the longitudinal (QY) and vertical (QZ) directions. However, the verification of the field piezometric versus the modeling heads showed the possibility of blockage of the finger drain.

The stability of slopes or the occurrence of mass movements is directly related to the incidence of rainfall. In this work a qualitative analysis of the historical series was made for the period between May 2012 and February 2019, where the development of pore pressures was evaluated, analyzing the behaviors of the instruments, correlating their readings with precipitation and with variations in the water table. Pore pressure was measured using vibrating wire piezometers, and precipitation data was collected using pluviometers with tipper buckets, whose readings were obtained by a datalogger model ML1-FL. From the data collected, it was possible to estimate the duration of a rainfall event for the soil, as that time interval between the occurrence of rain and the dissipation of excess pore pressure. These intervals are between 3 and 26 days in duration. The main results were: the period between the end of June and August is the driest and the highest precipitation occurs from December to early June; Precipitation of up to 100 mm of daily accumulation is well distributed throughout the year and occurs in all seasons. The pore pressure values developed were low, with a maximum of 9.3 kPa for the deepest piezometer on elevation 92.40 m. There is a delay between the occurrence of precipitation and the recording of the peak pore pressure. The in-depth knowledge of variations in precipitation and pore pressure can support the development of more robust geotechnical engineering projects. This preventive approach, based on concrete data and correlations, offers a more reliable strategy for mitigating the risks associated with landslides, directly contributing to the safety and continuous operation of the BR-101/SC highway.

Due to its inherent advantages, shield tunnelling has become the primary construction method for urban tunnels, such as high-speed railway and metro tunnels. However, there are numerous technical challenges to shield tunnelling in complex geological conditions. Under the disturbance induced by shield tunnelling, sandy pebble soil is highly susceptible to ground loss and disturbance, which may subsequently lead to the risk of surface collapse. In this paper, large-diameter slurry shield tunnelling in sandy pebble soil is the engineering background. A combination of field monitoring and numerical simulation is employed to analyze tunnelling parameters, surface settlement, and deep soil horizontal displacement. The patterns of ground disturbance induced by shield tunnelling in sandy pebble soil are explored. The findings reveal that slurry pressure, shield thrust, and cutterhead torque exhibit a strong correlation during shield tunnelling. In silty clay sections, surface settlement values fluctuate significantly, while in sandy pebble soil, the settlement remains relatively stable. The longitudinal horizontal displacement of deep soil is significantly greater than the transverse horizontal displacement. In order to improve the surface settlement troughs obtained by numerical simulation, a cross-anisotropic constitutive model is used to account for the anisotropy of the soil. A sensitivity analysis of the cross-anisotropy parameter alpha was performed, revealing that as alpha increases, the maximum vertical displacement of the ground surface gradually decreases, but the rate of decrease slows down and tends to level off. Conversely, as the cross-anisotropy parameter alpha decreases, the width of the settlement trough narrows, improving the settlement trough profile.

Rolling dynamic compaction (RDC) has been found to be useful for compaction soils and is now widely used globally. Because RDC is not often used in soft soils with poor engineering properties, field monitoring was used to study the soft clay embankment responses under RDC conditions in this study. Analysis of the monitoring data revealed that the response of the soil occurred mainly in the first 20 passes. Field monitoring revealed a strong correlation between settlement, horizontal displacement, and pore water pressure. The depth of impact of RDC on the soft soil embankment was between 3 and 3.5 m. Although settlement prediction is an important issue for construction, there is a lack of prediction methods for RDC-induced soil settlement. In this study, we used three different machine learning algorithms: random forest regression (RFR), multilayer perceptron (MLP), and extreme gradient boosting (XGBoost) to predict the total settlement and uneven settlement induced by RDC on the soft soil embankment. The three prediction models were compared, and the predictive accuracy of these models was assessed. This study analyzes and summarizes the effect of RDC application on a soft clay embankment and explores the machine learning method used for settlement prediction based on monitoring data, which provides some methods and ideas for research on the application of RDC on soft soil foundations.

A large-scale foundation pit with an area of 39,677 m2 (B2) was excavated to the south of an existing 25,720 m2 Chengdu Universal Trade Plaza (CDUTP) foundation pit (B1) in Chengdu, China. The purpose of this manuscript was to investigate the deformation characteristics of B2 and compare the difference of deformation characteristics between foundation pits B1 and B2. Direct monitoring results of foundation pit B2 were comprehensively investigated and compared with that observed in B1, which include lateral movement, column movement, stress in the columns, and axis force in the anchor cable. Additionally, a strategic approach to mitigate potential extensive lateral deformation was introduced. The monitored results for B2 revealed that the deflection and vertical movement of the columns were comparatively smaller than the reported lower boundaries. The maximum excavation-induced lateral column deflection exhibited a notable 35% reduction in comparison to the lateral deflection observed in the new excavation. However, vertical column movements were approximately twice as pronounced as those in B1. Furthermore, the installation of temporary columns with anchor cables in front of permanent columns proved effective in limiting the vertical deformation during excavation in close proximity to the permanent columns. This research provides valuable insights into the documentation of large-size excavations in soft soil, along with corresponding mitigation approaches.