Evaluation of excavation damaged zones(EDZs)in Horonobe Underground Research Laboratory(URL)

Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.

Micro-macro evolution of mechanical behaviors of thermally damaged rock:A state-of-the-art review

The influence of thermal damage on macroscopic and microscopic characteristics of different rocks has received much attention in the field of rock engineering.When the rocks are subjected to thermal treatment,the change of macroscopic characteristics and evolution of micro-structure would be induced,ultimately resulting in different degrees of thermal damage in rocks.To better understand the thermal damage mechanism of different rocks and its effect on the rock performance,this study reviews a large number of test results of rock specimens experiencing heating and cooling treatment in the laboratory.Firstly,the variations of macroscopic behaviors,including physical parameters,mechanical parameters,thermal conductivity and permeability,are examined.The variations of mechanical parameters with thermal treatment variables(i.e.temperature or the number of thermal cycles)are divided into four types.Secondly,several measuring methods for microstructure,such as polarizing microscopy,fluorescent method,scanning electron microscopy(SEM),X-ray computerized tomography(CT),acoustic emission(AE)and ultrasonic technique,are introduced.Furthermore,the effect of thermal damage on the mechanical parameters of rocks in response to different thermal treatments,involving temperature magnitude,cooling method and thermal cycle,are discussed.Finally,the limitations and prospects for the research of rock thermal damage are proposed.

Field survey and analysis on near-fault severely damaged high-speed railway bridge in 2022 M6.9 Menyuan earthquake

The 2022 M6.9 Menyuan earthquake caused severe damage to a high-speed railway bridge,which was designed for high-speed trains running at speeds of above 250 km/h and is located right next to the fault.Bridges of this type have been widely used for rapidly constructing the high-speed railway network,but few bridges have been tested by near-fault devastating earthquakes.The potential severe impact of the earthquake on the high-speed railway is not only the safety of the infrastructure,trains and passengers,but also economic loss due to interrupted railway use.Therefore,a field survey was carried out immediately after the earthquake to collect time-sensitive data.The damage to the bridge was carefully investigated,and quantitative analyses were conducted to better understand the mechanism of the bridge failure.It was found that seismic action perpendicular to the bridge’s longitudinal direction caused severe damage to the girders and rails,while none of the piers showed obvious deformation or cracking.The maximum values of transverse displacement,out-of-plane rotation and twisting angle of girders reached 212.6 cm,3.1 degrees and 19.9 degrees,respectively,causing severe damage to the bearing supports and anti-seismic retaining blocks.These observations provide a basis for improving the seismic design of high-speed railway bridges located in near-fault areas.

Anti-inflammatory and DNA Repair Effects of Astragaloside IV on PC12 Cells Damaged by Lipopolysaccharide

Objective This study aimed to establish a neural cell injury model in vitro by stimulating PC12 cells with lipopolysaccharide(LPS)and to examine the effects of astragaloside IV on key targets using high-throughput sequence technology and bioinformatics analyses.Methods PC12 cells in the logarithmic growth phase were treated with LPS at final concentrations of 0.25,0.5,0.75,1,and 1.25 mg/mL for 24 h.Cell morphology was evaluated,and cell survival rates were calculated.A neurocyte inflammatory model was established with LPS treatment,which reached a 50%cell survival rate.PC12 cells were treated with 0.01,0.1,1,10,or 100µmol/L astragaloside IV for 24 h.The concentration of astragaloside IV that did not affect the cell survival rate was selected as the treatment group for subsequent experiments.NOS activity was detected by colorimetry;the expression levels of ERCC2,XRCC4,XRCC2,TNF-α,IL-1β,TLR4,NOS and COX-2 mRNA and protein were detected by RT-qPCR and Western blotting.The differentially expressed genes(DEGs)between the groups were screened using a second-generation sequence(fold change>2,P<0.05)with the following KEGG enrichment analysis,RT-qPCR and Western blotting were used to detect the mRNA and protein expression of DEGs related to the IL-17 pathway in different groups of PC12 cells.Results The viability of PC12 cells was not altered by treatment with 0.01,0.1,or 1µmol/L astragaloside IV for 24 h(P>0.05).However,after treatment with 0.5,0.75,1,or 1.25 mg/mL LPS for 24 h,the viability steadily decreased(P<0.01).The mRNA and protein expression levels of ERCC2,XRCC4,XRCC2,TNF-α,IL-1β,TLR4,NOS,and COX-2 were significantly increased after PC12 cells were treated with 1 mg/mL LPS for 24 h(P<0.01);however,these changes were reversed when PC12 cells were pretreated with 0.01,0.1,or 1µmol/L astragaloside IV in PC12 cells and then treated with 1 mg/mL LPS for 24 h(P<0.05).Second-generation sequencing revealed that 1026 genes were upregulated,while 1287 genes were downregulated.The DEGs were associated with autophagy,TNF-α,interleukin-17,MAPK,P53,Toll-like receptor,and NOD-like receptor signaling pathways.Furthermore,PC12 cells treated with a 1 mg/mL LPS for 24 h exhibited increased mRNA and protein expression of CCL2,CCL11,CCL7,MMP3,and MMP10,which are associated with the IL-17 pathway.RT-qPCR and Western blotting analyses confirmed that the DEGs listed above corresponded to the sequence assay results.Conclusion LPS can damage PC12 cells and cause inflammatory reactions in nerve cells and DNA damage.astragaloside IV plays an anti-inflammatory and DNA damage protective role and inhibits the IL-17 signaling pathway to exert a neuroprotective effect in vitro.

Cholesterol and Sericin as First Aid for Damaged Cells

Cells are surrounded by a double-layered phospholipid cell membrane responsible for the isolation of intracellular contents, active regulation of uptake from the extracellular environment, and intercellular connection and communication. These cell membranes must be intact and functionally active for cell survival and biological functioning. Compromised damage repair mechanisms usually result in impaired cellular homeostasis, leading to early or late problems. Chronic myopathies, certain myocardial diseases, aging, and acute or chronic neurodegenerative diseases (like Parkinson and Alzheimer) are directly related to cell membrane damage. This study examined the effect of a cholesterol-loaded nanoparticle (methyl-beta cyclodextrin) or the silk protein sericin on cell membrane and DNA integrity and cell viability in an in vitro cell damage model (frozen-thawed rabbit sperm cells). The cells were stored in liquid nitrogen (-196°C), thawed in small batches, and treated with cholesterol-loaded cyclodextrin or sericin before incubation at 35°C for 4 hours. Cell membrane integrity, DNA damage, and viability rates were assessed immediately after thawing and after the incubation period. The administration of sericin and cholesterol in a cell damage model increased cell survival and reduced DNA damage over a 4-hour post-thaw incubation period, suggesting their potential use as a “first aid” intervention at the cellular level.

Predicting the Thickness of an Excavation Damaged Zone around the Roadway Using the DA-RF Hybrid Model

After the excavation of the roadway,the original stress balance is destroyed,resulting in the redistribution of stress and the formation of an excavation damaged zone(EDZ)around the roadway.The thickness of EDZ is the key basis for roadway stability discrimination and support structure design,and it is of great engineering significance to accurately predict the thickness of EDZ.Considering the advantages of machine learning(ML)in dealing with high-dimensional,nonlinear problems,a hybrid prediction model based on the random forest(RF)algorithm is developed in this paper.The model used the dragonfly algorithm(DA)to optimize two hyperparameters in RF,namely mtry and ntree,and used mean absolute error(MAE),rootmean square error(RMSE),determination coefficient(R^(2)),and variance accounted for(VAF)to evaluatemodel prediction performance.A database containing 217 sets of data was collected,with embedding depth(ED),drift span(DS),surrounding rock mass strength(RMS),joint index(JI)as input variables,and the excavation damaged zone thickness(EDZT)as output variable.In addition,four classic models,back propagation neural network(BPNN),extreme learning machine(ELM),radial basis function network(RBF),and RF were compared with the DA-RF model.The results showed that the DARF mold had the best prediction performance(training set:MAE=0.1036,RMSE=0.1514,R^(2)=0.9577,VAF=94.2645;test set:MAE=0.1115,RMSE=0.1417,R^(2)=0.9423,VAF=94.0836).The results of the sensitivity analysis showed that the relative importance of each input variable was DS,ED,RMS,and JI from low to high.

Intelligent Risk-Identification Algorithm with Vision and 3D LiDAR Patterns at Damaged Buildings

Existingfirefighting robots are focused on simple storage orfire sup-pression outside buildings rather than detection or recognition.Utilizing a large number of robots using expensive equipment is challenging.This study aims to increase the efficiency of search and rescue operations and the safety offirefigh-ters by detecting and identifying the disaster site by recognizing collapsed areas,obstacles,and rescuers on-site.A fusion algorithm combining a camera and three-dimension light detection and ranging(3D LiDAR)is proposed to detect and loca-lize the interiors of disaster sites.The algorithm detects obstacles by analyzingfloor segmentation and edge patterns using a mask regional convolutional neural network(mask R-CNN)features model based on the visual data collected from a parallelly connected camera and 3D LiDAR.People as objects are detected using you only look once version 4(YOLOv4)in the image data to localize persons requiring rescue.The point cloud data based on 3D LiDAR cluster the objects using the density-based spatial clustering of applications with noise(DBSCAN)clustering algorithm and estimate the distance to the actual object using the center point of the clustering result.The proposed artificial intelligence(AI)algorithm was verified based on individual sensors using a sensor-mounted robot in an actual building to detectfloor surfaces,atypical obstacles,and persons requiring rescue.Accordingly,the fused AI algorithm was comparatively verified.

Progress and Prospects of the Natural Restoration of Damaged Vegetation after the Earthquake

Vegetation plays an important role in soil and water conservation, water conservation and carbon sequestration of an ecosystem. The restoration of damaged vegetation is of great significance to the maintenance of species diversity and the restoration of the regional ecological environment. It is also one of the most effective measures to improve the fragile ecosystem. This paper summarizes the research results from decades of damaged vegetation recovery in the process of vegetation recovery, the main driving factor and the restoration mode.

An Analysis of the Dynamic Behavior of Damaged Reinforced Concrete Bridges under Moving Vehicle Loads by Using the Moving Mesh Technique

This work proposes a numerical investigation on the effects of damage on the structural response of Reinforced Concrete(RC)bridge structures commonly adopted in highway and railway networks.An effective three-dimensional FE-based numerical model is developed to analyze the bridge’s structural response under several damage scenarios,including the effects of moving vehicle loads.In particular,the longitudinal and transversal beams are modeled through solid finite elements,while horizontal slabs are made of shell elements.Damage phenomena are also incorporated in the numerical model according to a smeared approach consistent with Continuum Damage Mechanics(CDM).In such a context,the proposed method utilizes an advanced and efficient computational strategy for reproducing Vehicle-Bridge Interaction(VBI)effects based on a moving mesh technique consistent with the Arbitrary Lagrangian-Eulerian(ALE)formulation.The proposed model adopts a moving mesh interface for tracing the positions of the contact points between the vehicle’s wheels and the bridge slabs.Such modeling strategy avoids using extremely refined discretization for structural members,thus drastically reducing computational efforts.Vibrational analyses in terms of damage scenarios are presented to verify how the presence of damage affects the natural frequencies of the structural system.In addition,a comprehensive investigation regarding the response of the bridge under moving vehicles is developed,also providing results in terms of Dynamic Amplification Factor(DAFs)for typical design bridge variables.

Relationships between Froze Damaged and Tree-measuring Factors of Huodendron biaristatum Species in Damingshan

[Objective] The aim was to provide a reference for studying the resistant ability of subtropical forest to freeze disaster and detecting the recovery and evolution of Huodendron biaristatum species after freeze disaster.[Method] Effects of the damage caused by the southern ice storm in early 2008 on Huodendron biaristatum,dominant species of evergreen broad-leaved forest on the Damingshan,were studied in the aspect of population ecology.[Result] Among the 1 090 Huodendron biaristatum individuals （DBH ≥ 1 cm）,697 individuals were victims,accounting for 63.9%.The largest part of the victims was crown breakdown,which took up 37.6%.13.0% of the victims were bent,and 10.2% of the victims were trunk broken.The least part of the victims were uprooted,accounting for only 3.1%.Different types and extent of forestry damage had remarkable differences in diameter class,tree height,crown and taper.Rates of damage and crown breakdown increased with the increase of DBH,while bent rate decreased.Rates of damage,bent and trunk broken declined slowly with the increase of tree height,while crown breakdown rate followed the normal distribution.As the crown level increased,rates of damage and crown breakdown increased,while the rate of trunk broken decreased.Individuals with high taper were more susceptible to crown damage,bending,breaking and uprooted.[Conclusion] The resistant ability of Huodendron biaristatum species to freeze disaster is affected by many factors like DBH,tree height,crown,taper,etc..Huodendron biaristatum species in Damingshan affected by those factors show various kinds of damaged types dominant by mechanical damage,but there is few individual to die.

Extracting Feature Bands for Damaged Rice Leaves by Planthoppers Using Multi-spectral Imaging Technology

[Objective] The aim of this study was to extract effective feature bands of damaged rice leaves by planthoppers to make identification and classification rapidly from great amounts of imaging spectral data. [Method] The experiment, using multi-spectral imaging system, acquired the multi-spectral images of damaged rice leaves from band 400 to 720 nm by interval of 5 nm. [Result] According to the principle of band index, it was calculated that the bands at 515, 510, 710, 555, 630, 535, 505, 530 and 595 nm were having high band index value with rich information and little correlation. Furthermore, the experiment used two classification methods and calcu-lated the classification accuracy higher than 90.00% for feature bands and ful bands of damaged rice leaves by planthoppers respectively. [Conclusion] It can be con-cluded that these bands can be considered as effective feature bands to identify damaged rice leaves by planthoppers quickly from a large scale of crops.

Assessing fracturing mechanisms and evolution of excavation damaged zone of tunnels in interlocked rock masses at high stresses using a finitediscrete element approach

Deep underground excavations within hard rocks can result in damage to the surrounding rock mass mostly due to redistribution of stresses.Especially within rock masses with non-persistent joints,the role of the pre-existing joints in the damage evolution around the underground opening is of critical importance as they govern the fracturing mechanisms and influence the brittle responses of these hard rock masses under highly anisotropic in situ stresses.In this study,the main focus is the impact of joint network geometry,joint strength and applied field stresses on the rock mass behaviours and the evolution of excavation induced damage due to the loss of confinement as a tunnel face advances.Analysis of such a phenomenon was conducted using the finite-discrete element method (FDEM).The numerical model is initially calibrated in order to match the behaviour of the fracture-free,massive Lac du Bonnet granite during the excavation of the Underground Research Laboratory (URL) Test Tunnel,Canada.The influence of the pre-existing joints on the rock mass response during excavation is investigated by integrating discrete fracture networks (DFNs) of various characteristics into the numerical models under varying in situ stresses.The numerical results obtained highlight the significance of the pre-existing joints on the reduction of in situ rock mass strength and its capacity for extension with both factors controlling the brittle response of the material.Furthermore,the impact of spatial distribution of natural joints on the stability of an underground excavation is discussed,as well as the potentially minor influence of joint strength on the stress induced damage within joint systems of a non-persistent nature under specific conditions.Additionally,the in situ stress-joint network interaction is examined,revealing the complex fracturing mechanisms that may lead to uncontrolled fracture propagation that compromises the overall stability of an underground excavation.

Real-time reliability evaluation based on damaged measurement degradation data

A method was proposed to evaluate the real-time reliability for a single product based on damaged measurement degradation data.Most researches on degradation analysis often assumed that the measurement process did not have any impact on the product's performance.However,in some cases,the measurement process may exert extra stress on products being measured.To obtain trustful results in such a situation,a new degradation model was derived.Then,by fusing the prior information of product and its own on-line degradation data,the real-time reliability was evaluated on the basis of Bayesian formula.To make the proposed method more practical,a procedure based on expectation maximization (EM) algorithm was presented to estimate the unknown parameters.Finally,the performance of the proposed method was illustrated by a simulation study.The results show that ignoring the influence of the damaged measurement process can lead to biased evaluation results,if the damaged measurement process is involved.

Evaluation of Blast-Resistant Performance Predicted by Damaged Plasticity Model for Concrete

in order to evaluate the capacity of reinforced concrete （RC） structures subjected to blast Ioadings, the damaged plasticity model for concrete was used in the analysis of the dynamic responses of blast-loaded RC structures, and all three failure modes were numerically simulated by the finite element software ABAQUS. Simulation results agree with the experimental observations. It is demonstrated that the damaged plasticity model for concrete in the finite element software ABAQUS can predict dynamic responses and typical flexure, flexure-shear and direct shear failure modes of the blast-loaded RC structures.

Physical energies to the rescue of damaged tissues

Rhythmic oscillatory patterns sustain cellular dynamics, driving the concerted action of regulatory molecules, microtubules, and molecular motors. We describe cellular microtubules as oscillators capable of synchronization and swarming, generating mechanical and electric patterns that impact biomolecular recognition. We consider the biological relevance of seeing the inside of cells populated by a network of molecules that behave as bioelectronic circuits and chromophores. We discuss the novel perspectives disclosed by mechanobiology, bioelectromagnetism, and photobiomodulation, both in term of fundamental basic science and in light of the biomedical implication of using physical energies to govern (stem) cell fate. We focus on the feasibility of exploiting atomic force microscopy and hyperspectral imaging to detect signatures of nanomotions and electromagnetic radiation (light), respectively, generated by the stem cells across the specification of their multilineage repertoire. The chance is reported of using these signatures and the diffusive features of physical waves to direct specifically the differentiation program of stem cells in situ, where they already are resident in all the tissues of the human body. We discuss how this strategy may pave the way to a regenerative and precision medicine without the needs for (stem) cell or tissue transplantation. We describe a novel paradigm based upon boosting our inherent ability for self-healing.

Predicting the excavation damaged zone within brittle surrounding rock masses of deep underground caverns using a comprehensive approach integrating in situ measurements and numerical analysis

Excavation Damaged Zone(EDZ)scope is important for optimizing excavation and support schemes in deep underground caverns.However,accurately predicting the full EDZ scope within the surrounding rock masses of deep underground caverns during excavation remains a pressing problem.This study presents a comprehensive EDZ scope prediction approach(CESPA)for the brittle surrounding rock masses of deep underground caverns by coupling numerical simulation with quantitative analysis of borehole wall images and ultrasonic test results.First,the changes in both P-velocity(V_(p))and joint distribution of the surrounding rock masses before and after excavation damage are captured using ultrasonic tests and borehole digital cameras.Second,the quality Q-parameters of the surrounding rock mass before and after excavation damage are preliminarily rated with the rock mass descriptions provided by borehole wall images,and the rock mass V_(p)-parameter values are determined according to the V_(p)-borehole depth curves.Third,the Q-parameter ratings are further finely adjusted by updating the related Q-values to be similar with the Q-values estimated by V_(p)-parameter values.Fourth,the initial and residual mechanical parameters for the rock mass deterioration model(RDM)are estimated by the adjusted Q-parameter ratings based on the modified Q-based relations,and the elastic modulus deterioration index(EDI)threshold to describe the EDZ boundary is determined with the V_(p)-parameter values.Finally,EDZ scope is predicted using the elastoplastic numerical simulation with RDM and EDI based on the mechanical parameter estimates and EDI threshold.Analyses of applications in Sub-lab D1 in Jinping II project show that CESPA can provide a reliable and operable solution for predicting full EDZ scopes within the brittle surrounding rock masses of deep underground caverns.

Permeability and pressure distribution characteristics of the roadway surrounding rock in the damaged zone of an excavation

Research on the permeability and pressure distribution characteristics of the roadway surrounding rock in the excavation damaged zone(EDZ) is beneficial for the development of gas control technology. In this study, analytical solutions of stress and strain of the roadway surrounding rock were obtained, in which the creep deformation and strain softening were considered. Using the MTS815 rock mechanics testing system and a gas permeability testing system, permeability tests were conducted in the complete stress-strain process, and the evolution characteristics of permeability and strain were studied over the whole loading process. Based on the analytical solutions of stress and strain and the governing equation of gas seepage flow, this paper proposes a hydro-mechanical(HM) model, which considers three different zones around the roadway. Then the gas flow process in the roadway surrounding rock in three different zones was simulated according to the engineering geological conditions, thus obtaining the permeability and pressure distribution characteristics of the roadway surrounding rock in three different zones. These results show that the surrounding rock around the roadway can be divided into four regions-the full flow zone(FFZ), flow-shielding zone(FSZ), transitive flow zone(TFZ), and in-situ rock flow zone(IRFZ). These results could provide theoretical guidance for the improvement of gas extraction and gas control technology.

Raman Back-scattering study of Damaged and Strain Subsurface Layers in GaAs Wafers

The damaged and strain subsurface layers of semi insulating(SI) GaAs substrate were characterized non destructively by Raman back scattering.The study shows that the thicknesses of the damaged and strain layers are less than 3μm.The damaged and strain layer can be removed after being etched in H 2SO 4·H 2O 2·H 2O for 1.5 min.

Neuronal circuitry reconstruction after stem cell therapy in damaged brain

Transplantation of neuronal precursors derived from human pluripotent stem cells is a promising therapy for the treatment of neurological disorders associated with neuronal loss,such us neurodegenerative diseases,brain trauma and stroke.The functional integration of grafted neurons differentiated from stem cells into the host injured neuronal circuitry has been a major challenge in cell therapy strategies for brain repair(Palma-Tortosa et al.,2021).Even though other cell types or mechanisms may provide modest clinical improvements,neuronal replacement and reconstruction of the damaged area are crucial for an optimal and long-term recovery.

Protection of Environment from Damaged Nuclear Station and Transparent Inflatable Blanket for Cities—Protection from Radioactive Dust and Chemical, Biological Weapons

The author, in a series of previous articles, designed the “AB Dome” made of transparent thin film supported by a small additional air overpressure for the purpose of covering a city or other important large installations or sub-regions. In present article the author offers a variation in which a damaged nuclear station can be quickly covered by such a cheap inflatable dome. By containing the radioactive dust from the damaged nuclear station, the danger zone is reduced to about 2 km2 rather than large regions which requires the resettlement of huge masses of people and which stops indus-try in large areas. If there is a big city (as Tokyo) near the nuclear disaster or there is already a dangerous amount of radioactive dust near a city, the city may also be covered by a large inflatable transparent Dome. The building of a gi-gantic inflatable AB Dome over an empty flat surface is not difficult. The cover is spread on a flat surface and a venti-lator (fan system) pumps air under the film cover and lifts the new dome into place but inflation takes many hours. However, to cover a city, garden, forest or other obstacle course in contrast to an empty, mowed field, the thin film cannot be easily deployed over building or trees without risking damage to it by snagging and other complications. This article proposes a new method which solves this problem. The design is a double film blanket filled by light gas such as, methane, hydrogen, or helium - although of these, methane will be the most practical and least likely to leak. Sections of this AB Blanket are lighter than air and will rise in the atmosphere. They can be made on a flat area serving as an as-sembly area and delivered by dirigible or helicopter to station at altitude over the city. Here they connect to the already assembled AB Blanket subassemblies, cover the city in an AB Dome and protect it from bad weather, chemical, bio-logical and radioactive fallout or particulates. After assembly of the dome is completed, the light gas can be replaced by (heavier but cheaper) air. Two projects for Tokyo (Japan) and Moscow (Russia) are used in this paper for sample computation.