Thermo-hydro-poro-mechanical responses of a reservoir-induced landslide tracked by high-resolution fiber optic sensing nerves

Thermo-poro-mechanical responses along sliding zone/surface have been extensively studied.However,it has not been recognized that the potential contribution of other crucial engineering geological interfaces beyond the slip surface to progressive failure.Here,we aim to investigate the subsurface multiphysics of reservoir landslides under two extreme hydrologic conditions(i.e.wet and dry),particularly within sliding masses.Based on ultra-weak fiber Bragg grating(UWFBG)technology,we employ specialpurpose fiber optic sensing cables that can be implanted into boreholes as“nerves of the Earth”to collect data on soil temperature,water content,pore water pressure,and strain.The Xinpu landslide in the middle reach of the Three Gorges Reservoir Area in China was selected as a case study to establish a paradigm for in situ thermo-hydro-poro-mechanical monitoring.These UWFBG-based sensing cables were vertically buried in a 31 m-deep borehole at the foot of the landslide,with a resolution of 1 m except for the pressure sensor.We reported field measurements covering the period 2021 and 2022 and produced the spatiotemporal profiles throughout the borehole.Results show that wet years are more likely to motivate landslide motions than dry years.The annual thermally active layer of the landslide has a critical depth of roughly 9 m and might move downward in warmer years.The dynamic groundwater table is located at depths of 9e15 m,where the peaked strain undergoes a periodical response of leap and withdrawal to annual hydrometeorological cycles.These interface behaviors may support the interpretation of the contribution of reservoir regulation to slope stability,allowing us to correlate them to local damage events and potential global destabilization.This paper also offers a natural framework for interpreting thermo-hydro-poro-mechanical signatures from creeping reservoir bank slopes,which may form the basis for a landslide monitoring and early warning system.

Low WT1 transcript levels at diagnosis predicted poor outcomes of acute myeloid leukemia patients with t(8;21) who received chemotherapy or allogeneic hematopoietic stem cell transplantation

Background:Acute myeloid leukemia(AML) with t(8;21) is a heterogeneous disease.Identifying AML patients with t(8;21) who have a poor prognosis despite achieving remission is important for determining the best subsequent therapy.This study aimed to evaluate the impact of Wilm tumor gene-1(WT1) transcript levels and cellular homolog of the viral oncogene v-KIT receptor tyrosine kinase(C-KIT) mutations at diagnosis,and RUNXTRUNX1T1 transcript levels after the second consolidation chemotherapy cycle on outcomes.Methods:Eighty-eight AML patients with t(8;21) who received chemotherapy only or allogeneic hematopoietic stem cell transplantation(allo-HSCT) were included.Patients who achieved remission,received two or more cycles of consolidation chemotherapy,and had a positive measureable residual disease(MRD) test result(defined as <3-log reduction in RUNX1-RUNX1T1 transcript levels compared to baseline) after 2-8 cycles of consolidation chemotherapy were recommended to receive allo-HSCT.Patients who had a negative MRD test result were recommended to receive further chemotherapy up to only 8 cycles.WT1 transcript levels and C-KIT mutations at diagnosis,and RUNX1-RUNX1T1 transcript levels after the second consolidation chemotherapy cycle were tested.Results:Patients who had a C-KIT mutation had significantly lower WTl transcript levels than patients who did not have a C-KIT mutation(6.7%± 10.6%vs.19.5%± 19.9%,P < 0.001).Low WTl transcript levels(<5.0%) but not C-KIT mutation at diagnosis,a positive MRD test result after the second cycle of consolidation chemotherapy,and receiving only chemotherapy were independently associated with high cumulative incidence of relapse in all patients(hazard ratio[HR]= 3.53,2.30,and 11.49;95%confidence interval[CI]1.64-7.62,1.82-7.56,and 4.43-29.82;P = 0.002,0.034,and <0.001,respectively);these conditions were also independently associated with low leukemia-free survival(HR =3.71,2.33,and 5.85;95%CI 1.82-7.56,1.17-4.64,and 2.75-12.44;P < 0.001,0.016,and <0.001,respectively) and overall survival(HR = 3.50,2.32,and 4.34;95%CI 1.56-7.82,1.09-4.97,and 1.98-9.53;P = 0.002,0.030,and <0.001,respectively) in all patients.Conclusions:Testing for WTl transcript levels at diagnosis in patients with AML and t(8;21) may predict outcomes in those who achieve remission.A randomized study is warranted to determine whether allo-HSCT can improve prognosis in these patients.

Influence of soil density on gas permeability and water retention in soils amended with in-house produced biochar

Biochar has been used as an environment-friendly enhancer to improve the hydraulic properties(e.g.suction and water retention)of soil.However,variations in densities alter the properties of the soil ebiochar mix.Such density variations are observed in agriculture(loosely compacted)and engineering(densely compacted)applications.The influence of biochar amendment on gas permeability of soil has been barely investigated,especially for soil with different densities.The major objective of this study is to investigate the water retention capacity,and gas permeability of biochar-amended soil(BAS)with different biochar contents under varying degree of compaction(DOC)conditions.In-house produced novel biochar was mixed with the soil at different amendment rates(i.e.biochar contents of 0%,5%and 10%).All BAS samples were compacted at three DOCs(65%,80%and 95%)in polyvinyl chloride(PVC)tubes.Each soil column was subjected to dryingewetting cycles,during which soil suction,water content,and gas permeability were measured.A simplified theoretical framework for estimating the void ratio of BAS was proposed.The experimental results reveal that the addition of biochar significantly decreased gas permeability kg as compared with that of bare soil(BS).However,the addition of 5%biochar is found to be optimum in decreasing kg with an increase of DOC(i.e.k_(g,65%)>k_(g,80%)>k_(g,95%))at a relatively low suction range(<200 kPa)because both biochar and compaction treatment reduce the connected pores.

Probing multi-physical process and deformation mechanism of a largescale landslide using integrated dual-source monitoring

The implementation of isolated heterologous monitoring systems for spatially distant borehole deployments often comes with substantial equipment costs,which can limit the effectiveness of geohazard mitigation and georisk management efforts.To address this,we have developed a novel monitoring system that integrates fiber Bragg grating(FBG)and microelectromechanical system(MEMS)techniques to capture soil moisture,temperature,sliding resistance,strain,surface tilt,and deep-seated inclination.This system enables real-time,simultaneous data acquisition and cross-validation analyses,offering a costeffective solution for monitoring critical parameters in geohazard-prone areas.We successfully applied this integrated monitoring system to the Xinpu landslide,an active super-large landslide located in the Three Gorges Reservoir Area(TGRA)of China.The resulting strain profile confirmed the presence of two shallow secondary sliding surfaces at depths of approximately 7 m and 12 m,respectively,in addition to the deep-seated sliding surface at a depth of28 m.The lower secondary sliding surface was activated by extreme precipitation,while the upper one was primarily driven by significant changes in reservoir water levels and secondarily triggered by concentrated rainfalls.Anti-slide piles have remarkably reinforced the upper moving masses but failed to control the lower ones.The gap between the pile heads and the soil amplified the rainwater erosion effect,creating a preferential channel for rainwater infiltration.Multi-physical measurements revealed a mixture of seepage-driven and buoyancy-driven behaviors within the landslide.This study offers an integrated dual-source multi-physical monitoring paradigm that enables collaborative management of multiple crucial boreholes on a large-scale landslide,and contributes to the evaluation and improvement of engineering measures in similar geological settings.

Evaluating mechanism and inconsistencies in hydraulic conductivity of unsaturated soil using newly proposed biochar conductivity factor

In the past few decades,numerous studies have been conducted to promote the use of biochar as a soil amendment and most recently,for compacted geo-engineered soils.In general,the definite trends of biochar effects on water retention and fertility of soils have been confirmed.However,the biochar effects on hydraulic conductivity,particularly unsaturated hydraulic conductivity of soil-biochar mix remain unclear,making it difficult to understand water seepage in both agricultural and geo-engineered infrastructures in semi-arid regions.This study examines the unsaturated hydraulic conductivity function derived based on the measurements of soil water characteristic curves of soil with biochar contents of 0%,5%and 10%.A new parameter“biochar conductivity factor(BCF)”is proposed to evaluate the inconsistency in reported biochar effects on soil hydraulic conductivity and to interpret it from various mechanisms(inter-and intra-pore space filling,cracking,aggregation,bio-film formation and piping/internal erosion).The impact of biochar content on unsaturated hydraulic conductivity appears to reduce as the soil becomes drier with minimal effect in residual zone.Qualitative comparison of near-saturated hydraulic conductivity with test results in the literature showed that the BCF is generally higher for smaller ratio of sand to fine content(clay and silt).Moreover,the particle size of biochar may have significant influence on soil permeability.Future scope of research has been highlighted with respect to biochar production for its applications in agriculture and geo-environmental engineering.Long term effects such as root decay and growth,aggregation and nutrient supply need to be considered.