Rock mass quality prediction on tunnel faces with incomplete multi-source dataset via tree-augmented naive Bayesian network

Rock mass quality serves as a vital index for predicting the stability and safety status of rock tunnel faces.In tunneling practice,the rock mass quality is often assessed via a combination of qualitative and quantitative parameters.However,due to the harsh on-site construction conditions,it is rather difficult to obtain some of the evaluation parameters which are essential for the rock mass quality prediction.In this study,a novel improved Swin Transformer is proposed to detect,segment,and quantify rock mass characteristic parameters such as water leakage,fractures,weak interlayers.The site experiment results demonstrate that the improved Swin Transformer achieves optimal segmentation results and achieving accuracies of 92%,81%,and 86%for water leakage,fractures,and weak interlayers,respectively.A multisource rock tunnel face characteristic(RTFC)dataset includes 11 parameters for predicting rock mass quality is established.Considering the limitations in predictive performance of incomplete evaluation parameters exist in this dataset,a novel tree-augmented naive Bayesian network(BN)is proposed to address the challenge of the incomplete dataset and achieved a prediction accuracy of 88%.In comparison with other commonly used Machine Learning models the proposed BN-based approach proved an improved performance on predicting the rock mass quality with the incomplete dataset.By utilizing the established BN,a further sensitivity analysis is conducted to quantitatively evaluate the importance of the various parameters,results indicate that the rock strength and fractures parameter exert the most significant influence on rock mass quality.

Effect of eccentric and inclined loading on the bearing capacity of strip footing placed on rock mass

This paper deals with the bearing capacity determination of strip footing on a rock mass in hilly area by considering the influence of inclined and eccentric loading. Applying the generalized HoekBrown failure criterion, the failure behavior of the rock mass is modeled with the help of the power cone programming in the lower bound finite element limit analysis framework. Using bearing capacity factor(Ns), the change in bearing capacity of the strip footing due to the occurrence of eccentrically inclined loading is presented. The variations of the magnitude of Ns are obtained by examining the effects of the Hoek-Brown rock mass strength parameters(uniaxial compressive strength(sci), disturbance factor(D), rock parameter(mi), and Geological Strength Index(GSI)) in the presence of different magnitudes of eccentricity(e) and inclination angle(λ) with respect to the vertical plane, and presented as design charts. Both the inclined loading modes, i.e., inclination towards the center of strip footing(+λ) and inclination away from the center of strip footing(-λ), are adopted to perform the investigation. In addition, the correlation between the input parameters and the corresponding output is developed by utilizing the artificial neural network(ANN). Additionally, from sensitivity analysis, it is observed that inclination angle(λ) is the most sensitive parameter. For practicing engineers, the obtained design equation and design charts can be beneficial to understand the bearing capacity variation in the existence of eccentrically inclined loading in mountain areas.

Evaluation of slope stability through rock mass classification and kinematic analysis of some major slopes along NH-1A from Ramban to Banihal, North Western Himalayas

The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic growth.Due to natural and artificial factors,frequency of slope instabilities along the networks has been increasing over last few decades.Assessment of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the year.Several rock mass classification methods are generally used to assess the strength and deformability of rock mass.This study assesses slope stability along the NH-1A of Ramban district of North Western Himalayas.Various structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 slopes.For evaluating the stability of these slopes,kinematic analysis was performed along with geological strength index(GSI),rock mass rating(RMR),continuous slope mass rating(CoSMR),slope mass rating(SMR),and Q-slope in the present study.The SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely unstable.The stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating(SSR)for the factor of safety(FoS)of 1.2 and 1 respectively.Q-slope with probability of failure(PoF)1%gives two slopes as stable slopes.Stable slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the FoS.The value ranges given by different empirical classifications were RMR(37-74),GSI(27.3-58.5),SMR(11-59),and CoSMR(3.39-74.56).Good relationship was found among RMR&SSR and RMR&GSI with correlation coefficient(R 2)value of 0.815 and 0.6866,respectively.Lastly,a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.

Numerical manifold method for thermo-mechanical coupling simulation of fractured rock mass

As a calculation method based on the Galerkin variation,the numerical manifold method(NMM)adopts a double covering system,which can easily deal with discontinuous deformation problems and has a high calculation accuracy.Aiming at the thermo-mechanical(TM)coupling problem of fractured rock masses,this study uses the NMM to simulate the processes of crack initiation and propagation in a rock mass under the influence of temperature field,deduces related system equations,and proposes a penalty function method to deal with boundary conditions.Numerical examples are employed to confirm the effectiveness and high accuracy of this method.By the thermal stress analysis of a thick-walled cylinder(TWC),the simulation of cracking in the TWC under heating and cooling conditions,and the simulation of thermal cracking of the SwedishÄspöPillar Stability Experiment(APSE)rock column,the thermal stress,and TM coupling are obtained.The numerical simulation results are in good agreement with the test data and other numerical results,thus verifying the effectiveness of the NMM in dealing with thermal stress and crack propagation problems of fractured rock masses.

Deformation characteristics and damage ontologies of soft and hard composite rock masses under impact loading

As one of the most common occurring geological landforms in deep rock formations, the dynamic mechanical properties of layered composite rock bodies under impact loading have been widely studied by scholars. To study the dynamic properties of soft and hard composite rocks with different thickness ratios, this paper utilizes cement, quartz sand and gypsum powder to construct soft and hard composite rock specimens and utilizes a combination of indoor tests, numerical calculations, and theoretical analyses to investigate the mechanical properties of soft and hard composite rock bodies. The test results reveal that:(1) When the proportion of hard rock increases from 20% to 50%, the strength of the combined rock body increases by 69.14 MPa and 87 MPa when the hard rock face and soft rock face are loaded, respectively;however, when the proportion of hard rock is the same, the compressive strength of the hard rock face impact is 9%-17% greater than that of the soft rock face impact;(2) When a specimen of soft and hard combined rock body is subjected to impact loading, the damage mode involves mixed tension and shear damage, and the cracks generally first appear at the ends of the specimen, then develop on the laminar surface from the impact surface, and finally end in the overall damage of the soft rock part. The development rate and the total number of cracks in the same specimen when the hard rock face is impacted are significantly greater than those when the soft rock face is impacted;(3) By introducing Weibull’s statistical strength theory to establish the damage variables of soft-hard combined rock bodies, combined with the DP strength criterion, the damage model and the Kelvin body are concatenated to obtain a statistical damage constitutive model, which can better fit the full stress-strain curve of soft-hard combined rock body specimens under a single impact load.

Investigation of anisotropic strength criteria for layered rock mass

Layered rock mass is a type of engineering rock mass with sound mechanical anisotropy,which is generally unfavorable to the stability of underground works.To investigate the strength anisotropy of layered rock,the Mohr-Coulomb and Hoek-Brown criteria are introduced to establish the two transverse isotropic strength criteria based on Jaeger's single weak plane theory and maximum axial strain theory,and parameter determination methods.Furthermore,the sensitivity of strength parameters(K 1,K 2,and K 3)that are used to characterize the anisotropy strength of non-sliding failure involved in the strength criteria and confining pressure are investigated.The results demonstrate that strength parameters K 1 and K 2 affect the strength of layered rock samples at all bedding angles except for the bedding angle of 90°and the angle range that can cause the shear sliding failure along the bedding plane.The strength of samples at any bedding angle decreases with increasing K 1,whereas the opposite is for K 2.Except for bedding angles of 0°and 90°and the bedding angle range that can cause the shear sliding along the bedding plane,K 3 has an impact on the strength of rock samples with other bedding angles that the specimens'strength increases with increase of K 3.In addition,the strength of the rock sample increases as confining pressure rises.Furthermore,the uniaxial and triaxial tests of chlorite schist samples were carried out to verify and evaluate the strength criteria proposed in the paper.It shows that the predicted strength is in good agreement with the experimental results.To test the applicability of the strength criterion,the strength data of several types of rock in the literature are compared.Finally,a comparison is made between the fitting effects of the two strength criteria and other available criteria for layered rocks.

Restraint effect of partition wall on the tunnel floor heave in layered rock mass

The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel floors.The results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal squeezing.With an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave deformation.The primary cause of significant deformation in floor heave is upward buckling failure.To address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock layers.The results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave deformation.It is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure stability.Through simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor.

A modified smoothed particle hydrodynamics method considering residual stress for simulating failure and its application in layered rock mass

Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating fracture.An improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and shear.Bond fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear damage.Numerical simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and separation.The results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock slopes.The residual stress of brittle tock is correctly captured by the improved SPH method.The improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical solutions.We infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.

Failure mechanism and safety control technology of a composite strata roadway in deep and soft rock masses:a case study

The construction of coal mines often encounters deep composite soft rock roadways,which is characterized by significant deformation and poor stability.To deeply study the failure mechanism and large deformation challenges of a composite strata roadway in deep and soft rock masses,a numerical model of 3DEC tetrahedral blocks was established based on the method of rock quality designation(RQD).The results showed that original support cannot prevent asymmetric failure and large deformation due to the adverse geological environment and unsuitable support design.According to the failure characteristics,a coupling support of“NPR bolt/cable+mesh+shotcrete+steel pipe”was proposed to control the stability of the surrounding rock.The excellent mechanical properties of large deformation(approximately 400 mm)and high constant resistance force(bolt with 180 k N;cable with 350 k N)were evaluated by the tensile tests.The numerical results showed that the maximum deformation was minimized to 243 mm,and the bearing capacity of the surrounding rock of the roadway was enhanced.The field test results showed that the maximum deformation of the surrounding rock was 210 mm,and the forces of the NPR bolt and cable were stable at approximately 180 k N and 350 k N,respectively.This demonstrated the effectiveness of the coupling support with the NPR bolt and cable,which could be a guiding significance for the safety control of large deformation and failure in deep composite soft rock roadways.

桃叶珊瑚苷调节RhoA/ROCK信号通路对胶质母细胞瘤细胞活力和上皮间质转化的影响

[目的]研究桃叶珊瑚苷(AU)对胶质母细胞瘤(GBM)细胞活力和上皮间质转化(EMT)的影响,并对其作用机制进行探讨。[方法]将U87细胞随机分为对照组、AU低浓度组、AU中浓度组、AU高浓度组、Y-27632组、AU高浓度+Y-27632组。细胞计数器试剂盒(CCK-8)法检测细胞活力,流式细胞术检测细胞凋亡,Transwell小室实验检测细胞迁移和侵袭,蛋白免疫印迹法(Western Blot)检测基质金属蛋白酶(MMP)2、MMP9、波形蛋白(Vimentin)、上皮钙黏蛋白(E-cadherin)、神经钙黏蛋白(N-cadherin)、Ras同源基因家族成员A(RhoA)、Rho相关卷曲螺旋蛋白激酶(ROCK)1、ROCK2表达。构建GBM裸鼠模型,随机分为裸鼠对照组、AU组、Y-27632组、AU+Y-27632组,测量肿瘤质量与体积,免疫组化法检测移植瘤组织RhoA、ROCK1、ROCK2蛋白表达。[结果]GBM细胞活力随着AU浓度的升高而逐渐降低(P<0.05),选择U87作为后续实验细胞,选择10、25、50μmol/L浓度作为AU后续实验浓度。与对照组比较,AU低、中、高浓度组和Y-27632组细胞活力、迁移和侵袭细胞数、MMP2、MMP9、N-cadherin、Vimentin、RhoA、ROCK1、ROCK2表达显著下降,凋亡率、E-cadherin表达显著升高(P<0.05),其中高浓度AU和Y-27632组共同处理的细胞变化更显著(P<0.05)。AU和Y-27632均能抑制移植瘤质量和体积,降低RhoA/ROCK信号通路蛋白表达(P<0.05)。[结论]AU能抑制GBM细胞活力、迁移侵袭和EMT,促进细胞凋亡,其作用机制可能与抑制RhoA/ROCK信号通路有关。

SLC9A3-AS1调控miR-148a-3p/ROCK1信号轴影响肾癌细胞生物学功能

目的检测lncRNA SLC9A3-AS1在肾透明细胞癌(clear cell renal cell carcinoma,ccRCC)组织与肾癌细胞中的表达水平,探讨其促进肾癌细胞恶性生物学行为的机制。方法应用GEPIA2在线软件(http://gepia2.cancer-pku.cn/)分析TCGA数据库中SLC9A3-AS1在ccRCC组织中的表达水平;采用实时荧光定量聚合酶链反应(qRT-PCR)检测SLC9A3-AS1在不同肾癌细胞系、24例ccRCC组织与癌旁正常肾脏组织中的表达水平;应用细胞增殖/毒性检测试剂盒(cell counting kit-8,CCK-8)和Transwell小室迁移实验检测敲低SLC9A3-AS1表达对肾癌细胞增殖与迁移的影响;应用蛋白质免疫印迹法检测增殖与迁移相关信号通路蛋白的表达水平;采用双荧光素酶报告基因实验验证SLC9A3-AS1与miR-148a-3p/ROCK1轴的靶向调控关系。结果GEPIA2软件分析结果显示,相较正常肾脏组织,SLC9A3-AS1在肾透明细胞癌组织中表达显著上调(P<0.01)。qRT-PCR结果显示,相较癌旁正常肾脏组织,SLC9A3-AS1在24例ccRCC组织中表达显著上调(P<0.01);相较永生化肾小管上皮细胞,SLC9A3-AS1在4种肾癌细胞系中表达均显著上调,以786-O细胞最为显著(P<0.01)。干扰SLC9A3-AS1表达,可显著抑制786-O细胞的增殖与迁移能力,上调E-cadherin的蛋白表达水平,而下调N-cadherin、MMP2的蛋白表达水平(均P<0.05);过表达miR-148a-3p可显著抑制786-O细胞的增殖与迁移能力(P<0.01)。双荧光素酶报告基因检测结果表明,SLC9A3-AS1可特异性结合miR-148a-3p,后者进一步靶向结合ROCK1 mRNA的3′UTR区域;过表达miR-148a-3p可明显下调ROCK1 mRNA的表达水平,敲低miR-148a-3p表达则产生相反的效应;敲低SLC9A3-AS1表达可显著下调786-O细胞中ROCK1 mRNA与蛋白的表达水平(P<0.01);下调miR-148a-3p表达可部分逆转SLC9A3-AS1沉默对786-O细胞增殖与迁移的抑制作用(P<0.05)。结论SLC9A3-AS1在ccRCC中通过调控miR-148a-3p/ROCK1轴发挥促癌作用,有望成为ccRCC的一个新的分子标志物。

Application and prospects of 3D printing in physical experiments of rock mass mechanics and engineering:materials,methodologies and models

The existence of joints or other kinds of discontinuities has a dramatic efect on the stability of rock excavations and engineering.As a result,a great challenge in rock mass mechanics testing is to prepare rock or rock-like samples with defects.In recent years,3D printing technology has become a promising tool in the feld of rock mass mechanics and engineering.This study frst reviews and discusses the research status of traditional test methods in rock mass mechanics tests of making rock samples with defects.Then,based on the comprehensive analysis of previous research,the application of 3D printing technology in rock mass mechanics is expounded from the following three aspects.The frst is the printing material.Although there are many materials for 3D printing,it has been found that 3D printing materials that can be used for rock mass mechanics research are very limited.After research,we summarize and evaluate printing material that can be used for rock mass mechanics studies.The second is the printing methodology,which mainly introduces the current application forms of 3D printing technology in rock mass mechanics.This includes printed precise casting molds and one-time printed samples.The last one is the printing model,which includes small-scale samples for mechanical tests and large-scale physical models.Then,the benefts and drawbacks of using 3D printing samples in mechanical tests and the validity of their simulation of real rock are discussed.Compared with traditional rock samples collected in nature or synthetic rock-like samples,the samples made by 3D printing technology have unique advantages,such as higher test repeatability,visualization of rock internal structure and stress distribution.There is thus great potential for the use of 3D printing in the feld of rock mass mechanics.However,3D printing materials also have shortcomings,such as insufcient material strength and accuracy at this stage.Finally,the application prospect of 3D printing technology in rock mass mechanics research is proposed.

A 3D microseismic data-driven damage model for jointed rock mass under hydro-mechanical coupling conditions and its application

Rock mass is a fractured porous medium usually subjected to complex geostress and fluid pressure simultaneously.Moreover,the properties of rock mass change in time and space due to mining-induced fractures.Therefore,it is always challenging to accurately measure rock mass properties.In this study,a three-dimensional(3D)microseismic(MS)data-driven damage model for jointed rock mass under hydro-mechanical coupling conditions is proposed.It is a 3D finite element model that takes seepage,damage and stress field effects into account jointly.Multiple factors(i.e.joints,water and microseismicity)are used to optimize the rock mass mechanical parameters at different scales.The model is applied in Shirengou iron mine to study the damage evolution of rock mass and assess the crown pillar stability during the transition from open-pit to underground mining.It is found that the damage pattern is mostly controlled by the structure,water and rock mass parameters.The damage pattern is evidently different from the two-dimensional result and is more consistent with the field observations.This difference is caused by the MS-derived damage acting on the rock mass.MS data are responsible for gradually correcting the damage zone,changing the direction in which it expands,and promoting it to evolve close to reality.For the crown pillar,the proposed model yields a more trustworthy safety factor.In order to guarantee the stability of the pillar,it is suggested to take waterproof and reinforcement measures in areas with a high degree of damage.

艾灸联合保真汤加减治疗糖尿病肾病的疗效观察及对CT灌注参数、Rho/ROCK信号通路蛋白的影响

目的 观察艾灸联合保真汤加减治疗糖尿病肾病气阴两虚证的临床疗效及对CT灌注参数、Rho/ROCK信号通路蛋白的影响。方法 将146例糖尿病肾病气阴两虚证患者随机分为观察组(74例)和对照组(72例)。在对症治疗的基础上,对照组给予厄贝沙坦片,观察组给予艾灸联合保真汤加减。观察两组中医主症积分、CT灌注参数[血尿素氮(blood urea nitrogen, BUN)、血肌酐(serum creatinine, SCr)、尿白蛋白排泄率(urinary albumin excretion rate, UAER)和24 h尿蛋白定量(24-hour urinary protein quantification, 24 h Upro)]、肾血流指标[舒张末期血流速度(end-diastolic velocity, EDV)、肾段动脉的收缩期峰值流速(peak-systolic velocity, PSV)、搏动指数(pulsatility index, PI)和阻力指数(resistive index, RI)]、血清炎性因子[肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)、白细胞介素-1β(interleukin-1β, IL-1β)、白细胞介素-6(interleukin-6, IL-6)和C反应蛋白(C-reactive protein, CRP)]水平及Rho/ROCK信号通路[Ras同源基因家族成员A(Ras homolog gene family member A, RhoA)、Rho关联含卷曲螺旋蛋白激酶Ⅰ(Rho-associated coiled-coil containing protein kinaseⅠ, ROCKI)、α-平滑肌肌动蛋白(α-smooth muscle actin, α-SMA)和钙黏附蛋白-E(E-cadherin, E-Cad)]蛋白水平,并比较两组临床疗效及不良反应。结果 观察组总有效率为97.3%(72/74),明显高于对照组的81.9%(59/72)(P<0.05)。观察组治疗后中医主症积分低于治疗前和对照组(P<0.05)。两组治疗后CT灌注参数降低(P<0.05),且观察组低于对照组(P<0.05)。观察组治疗后PSV、EDV较治疗前和对照组加快(P<0.05),RI、PI较治疗前和对照组降低(P<0.05)。观察组治疗后血清炎性因子水平较治疗前和对照组降低(P<0.05)。观察组治疗后Rho A、ROCKI、α-SMA蛋白水平较治疗前和对照组降低(P<0.05),E-Cad蛋白水平较治疗前和对照组升高(P<0.05)。观察组不良反应发生率为1.4%(1/74),低于对照组的19.4%(14/72)(P<0.05)。结论 在对症治疗的基础上,艾灸联合保真汤加减可明显提高糖尿病肾病气阴两虚证患者的治疗效果,其机制可能与改善CT灌注参数,调节血清Rho/ROCK信号通路蛋白相关。

Rock mass response for lined rock caverns subjected to high internal gas pressure

The storage of hydrogen gas in underground lined rock caverns(LRCs)enables the implementation of the first fossil-free steelmaking process to meet the large demand for crude steel.Predicting the response of rock mass is important to ensure that gas leakage due to rupture of the steel lining does not occur.Analytical and numerical models can be used to estimate the rock mass response to high internal pressure;however,the fitness of these models under different in situ stress conditions and cavern shapes has not been studied.In this paper,the suitability of analytical and numerical models to estimate the maximum cavern wall tangential strain under high internal pressure is studied.The analytical model is derived in detail and finite element(FE)models considering both two-dimensional(2D)and three-dimensional(3D)geometries are presented.These models are verified with field measurements from the LRC in Skallen,southwestern Sweden.The analytical model is inexpensive to implement and gives good results for isotropic in situ stress conditions and large cavern heights.For the case of anisotropic horizontal in situ stresses,as the conditions in Skallen,the 3D FE model is the best approach.

Determination of rock mass integrity coefficient using a non-invasive geophysical approach

Determination of rock mechanical parameters is the most important step in rock mass quality evaluation and has significant impacts on geotechnical engineering practice.Rock mass integrity coefficient(KV)is one of the most efficient parameters,which is conventionally determined from boreholes.Such approaches,however,are time-consuming and expensive,offer low data coverage of point measurements,require heavy equipment,and are hardly conducted in steep topographic sites.Hence,borehole approaches cannot assess the subsurface thoroughly for rock mass quality evaluation.Alternatively,use of geophysical methods is non-invasive,rapid and economical.The proposed geophysical approach makes useful empirical correlation between geophysical and geotechnical parameters.We evaluated the rock mass quality via integration between KV measured from the limited boreholes and inverted resistivity obtained from electrical resistivity tomography(ERT).The borehole-ERT correlation provided KV along various geophysical profiles for more detailed 2D/3D(two-/three-dimensional)mapping of rock mass quality.The subsurface was thoroughly evaluated for rock masses with different engineering qualities,including highly weathered rock,semi-weathered rock,and fresh rock.Furthermore,ERT was integrated with induced polarization(IP)to resolve the uncertainty caused by water/clay content.Our results show that the proposed method,compared with the conventional approaches,can reduce the ambiguities caused by inadequate data,and give more accurate insights into the subsurface for rock mass quality evaluation.

Rock mass quality classification based on deep learning:A feasibility study for stacked autoencoders

Objective and accurate evaluation of rock mass quality classification is the prerequisite for reliable sta-bility assessment.To develop a tool that can deliver quick and accurate evaluation of rock mass quality,a deep learning approach is developed,which uses stacked autoencoders(SAEs)with several autoencoders and a softmax net layer.Ten rock parameters of rock mass rating(RMR)system are calibrated in this model.The model is trained using 75%of the total database for training sample data.The SAEs trained model achieves a nearly 100%prediction accuracy.For comparison,other different models are also trained with the same dataset,using artificial neural network(ANN)and radial basis function(RBF).The results show that the SAEs classify all test samples correctly while the rating accuracies of ANN and RBF are 97.5%and 98.7%,repectively,which are calculated from the confusion matrix.Moreover,this model is further employed to predict the slope risk level of an abandoned quarry.The proposed approach using SAEs,or deep learning in general,is more objective and more accurate and requires less human inter-vention.The findings presented here shall shed light for engineers/researchers interested in analyzing rock mass classification criteria or performing field investigation.

黄芩苷通过ROS依赖性调节RhoA/ROCK通路保护氯化钴诱导心肌细胞损伤的实验研究

目的:本研究旨在探讨黄芩苷(Baicalin)对氯化钴(CoCl_(2))诱导H9c2心肌细胞缺氧损伤的作用机制。方法:采用CoCl_(2)建立心肌细胞缺氧损伤模型,并分别加入不同浓度的黄芩苷培养。将正常氧培养设置为对照组,CoCl_(2)培养H9c2心肌细胞设置为CoCl_(2)组;Baicalin、Y27632(Rho激酶抑制剂)预处理的H9c2缺氧心肌细胞设置为CoCl_(2)+Baicalin组、CoCl_(2)+Y27632组、CoCl_(2)+Baicalin+Y27632组。通过细胞毒性检测试剂盒(CCK8)检测细胞活性;荧光探针测定细胞中活性氧(ROS)的表达;WST-8检测心肌细胞超氧化歧化酶(SOD)活力;TBA法测定丙二醇(MDA)浓度;同时采用WesternBlot方法分析RhoA、ROCK1、ROCK2、TNF-α、IL-1β蛋白表达情况。结果:处理H9c2细胞24 h后,1 000μmol/L的CoCl_(2)和75μmol/L黄芩苷对治疗心肌细胞缺氧损伤具有较好的细胞活力。CoCl_(2)组细胞活性明显低于对照组,加入黄芩苷后可显著提高细胞活性(P<0.05);与对照组相比,CoCl_(2)组心肌细胞可上调ROS、MDA表达,下调SOD活力,升高RhoA、ROCK1、ROCK2、TNF-α、IL-1β蛋白表达水平,加入Baicalin后可逆转上诉蛋白的表达水平;与CoCl_(2)组相比,CoCl_(2)+Baicalin可抑制ROS、MDA的表达,上调SOD含量,下调RhoA、ROCK1、ROCK2、TNF-α、IL-1β蛋白表达水平,而加入Y27632(Rho激酶抑制剂)后则可显著增强Baicalin带来的保护作用。结论:Baicalin可减轻CoCl_(2)诱导H9c2心肌细胞缺氧损伤的炎症、氧化应激反应,其机制与抑制ROS依赖性RhoA/ROCK通路有关。

Characteristics and dynamic analysis of the February 2021 long-runout disaster chain triggered by massive rock and ice avalanche at Chamoli, Indian Himalaya

A massive rock and ice avalanche occurred on the western slope of the Ronti Gad valley in the northern part of Chamoli,Indian Himalaya,on 7 February 7,2021.The avalanche on the high mountain slope at an elevation of 5600 m above sea level triggered a long runout disaster chain,including rock mass avalanche,debris avalanche,and flood.The disaster chain had a horizontal travel distance of larger than 17,600 m and an elevation difference of 4300 m.In this study,the disaster characteristics and dynamic process were analyzed by multitemporal satellite imagery.The results show that the massive rock and ice avalanche was caused by four large expanding discontinuity planes.The disaster chain was divided into five zones by satellite images and field observation,including source zone,transition zone,dynamic entrainment zone,flow deposition zone,and flood zone.The entrainment effect and melting water were recognized as the main causes of the long-runout distance.Based on the seismic wave records and field videos,the time progress of the disaster was analyzed and the velocity of frontal debris at different stages was calculated.The total analyzed disaster duration was 1247 s,and the frontal debris velocity colliding with the second hydropower station was approximately 23 m/s.This study also carried out the numerical simulation of the disaster by rapid mass movement simulation(RAMMS).The numerical results reproduced the dynamic process of the debris avalanche,and the mechanism of long-runout avalanche was further verified by parametric study.Furthermore,this study discussed the potential causes of disaster and flood and the roles of satellite images and seismic networks in the monitoring and early-warning.

Multi-domain equivalent method for prediction of elastic modulus of complex fractured rock mass

Reliable estimation of deformation and failure behaviors of fractured rock mass is important for practical engineering design.This study proposes a multi-domain equivalent method for fracture network to estimate the deformation properties of complex fractured rock mass.It comprehends both the advantages of the discrete fracture network model and the equivalent continuum model to capture the features of discontinuities explicitly while reducing computational intensity.The complex fracture network is stochastically split into a number of subfracture networks according to the domain,length or angle.An analytical solution is derived to infer theoretically the relationship between the elastic moduli of the original complex fractured rock mass and the split subfractured rock masses by introducing a correction term based on the deformation superposition principle.Numerical simulations are conducted to determine the elastic moduli of split subfractured rock masses using universal distinct element code(UDEC),while the elastic modulus of the original model is estimated based on the currently proposed analytical relationship.The results show that the estimation accuracy with the current domainbased splitting model is far superior compared to those with the other two splitting models.Thus,the estimation method of elastic modulus of complex fractured rock mass based on domain splitting mode of fracture network is identified as the multi-domain equivalent method proposed in this paper.The reliability of this method is evaluated,and its high computational efficiency is demonstrated through exemplification with regard to different geometric configurations for stochastically artificial discrete fracture network.The proposed multi-domain equivalent method constructs the theoretical framework except for the regression analysis hypothesis compared to the density-reduced model equivalent method.