Study of hydro-mechanical behaviours of rough rock fracture with shear dilatancy and asperities using shear-flow model

The geometric properties of fracture surfaces significantly influence shear-seepage in rock fractures,introducing complexities to fracture modelling.The present study focuses on the hydro-mechanical behaviours of rough rock fractures during shear-seepage processes to reveal how dilatancy and fracture asperities affect these phenomena.To achieve this,an improved shear-flow model(SFM)is proposed with the incorporation of dilatancy effect and asperities.In particular,shear dilatancy is accounted for in both the elastic and plastic stages,in contrast to some existing models that only consider it in the elastic stage.Depending on the computation approaches for the peak dilatancy angle,three different versions of the SFM are derived based on Mohr-Coulomb,joint roughness coefficient-joint compressive strength(JRC-JCS),and Grasselli’s theories.Notably,this is a new attempt that utilizes Grasselli’s model in shearseepage analysis.An advanced parameter optimization method is introduced to accurately determine model parameters,addressing the issue of local optima inherent in some conventional methods.Then,model performance is evaluated against existing experimental results.The findings demonstrate that the SFM effectively reproduces the shear-seepage characteristics of rock fracture across a wide range of stress levels.Further sensitivity analysis reveals how dilatancy and asperity affect hydraulic properties.The relation between hydro-mechanical properties(dilatancy displacement and hydraulic conductivity)and asperity parameters is analysed.Several profound understandings of the shear-seepage process are obtained by exploring the phenomenon under various conditions.

Spatial deduction of mining-induced stress redistribution using an optimized non-negative matrix factorization model

Investigation of mining-induced stress is essential for the safety of coal production.Although the field monitoring and numerical simulation play a significant role in obtaining the structural mechanical behaviors,the range of monitoring is not sufficient due to the limits of monitoring points and the associated numerical result is not accurate.In this study,we aim to present a spatial deduction model to characterize the mining-induced stress distribution using machine learning algorithm on limited monitoring data.First,the framework of the spatial deduction model is developed on the basis of non-negative matrix factorization(NMF)algorithm and optimized by mechanical mechanism.In this framework,the spatial correlation of stress response is captured from numerical results,and the learned correlation is employed in NMF as a mechanical constrain to augment the limited monitoring data and obtain the overall mechanical performances.Then,the developed model is applied to a coal mine in Shandong,China.Experimental results show the stress distribution in one plane is derived by several monitoring points,where mining induced stress release is observed in goaf and stress concentration in coal pillar,and the intersection point between goaf and coal seam is a sensitive area.The indicators used to evaluate the property of the presented model indicate that 83%mechanical performances have been captured and the deduction accuracy is about 92.9%.Therefore,it is likely that the presented deduction model is reliable.

聚三唑酯树脂的合成及其性能

通过酯化反应合成丁二酸二炔丙醇酯(DPS)、间苯二甲酸二炔丙醇酯(DPIP)、对苯二甲酸二炔丙醇酯(DPP),与三官能团叠氮化合物(TAMTMB)反应,制备了3种热固性聚三唑酯(PTAE)树脂,研究了树脂的加工特性、固化行为、树脂固化物的力学性能,制备和表征了T700单向碳纤维增强PTAE树脂复合材料。结果表明,PTAE树脂具有良好的加工性能,可在较低温度(80℃)下固化;固化后的PTAE树脂的玻璃化转变温度(Tg)受主链结构影响,3种树脂的Tg均高于140℃,浇铸体弯曲强度高于170 MPa,T700单向纤维增强PTAE树脂复合材料的常温弯曲强度高于1 500 MPa。

不同放牧强度对赛罕乌拉草原蜘蛛多样性的影响

蜘蛛作为草原生态系统中的主要消费者,对维系草原生物多样性和生态系统功能具有重大意义。放牧是人类利用草原最普遍的方式,了解放牧对蜘蛛多样性的影响具有重要生态学意义。本研究调查了内蒙古赛罕乌拉草原上5个不同放牧强度样地中的蜘蛛多样性,通过单因素方差分析(one-wayanalysisofvariance)比较各样地中的蜘蛛多样性,非度量多维标度分析(non-metric multidimensional scale,NMDS)和相似性分析(analysis of similarities,ANOSIM)比较各样地间的蜘蛛物种组成相似性,再结合相关性分析探讨了植被高度对蜘蛛多样性的影响。结果表明:重度放牧强度样地的蜘蛛多样性显著低于其他未放牧及轻度放牧样地;具体到常见科上,放牧强度对织网型的园蛛物种数和个体数影响显著,而对游猎型的狼蛛、跳蛛却不明显;织网型蜘蛛主要受植被结构影响,而游猎型蜘蛛更可能受潜在猎物可得性的影响。NMDS分析表明不同放牧强度下,蜘蛛类群的物种组成呈现明显的梯度变化,放牧强度越低,物种组成和未放牧样地越相近。相关性分析表明草原植被高度与蜘蛛多样性总体上呈正相关关系,即植被高度越高,蜘蛛多样性越高。其中依靠植物构建蛛网的园蛛科和在植物上层伏击猎物的蟹蛛科、逍遥蛛科等与植被高度显著相关。这说明植物资源及其空间异质性可能对草原蜘蛛多样性起着主导作用。因此,降低放牧强度有助于保护草原蜘蛛群落的多样性,特别有利于织网型蜘蛛。

Superhydrophobic hierarchical porous divinylbenzene polymer for BTEX sensing and toluene/water selective detection

This work reports a superhydrophobic divinylbenzene polymer with hierarchical porous structure as sensing material to modify the quartz crystal microbalance(QCM)to detect benzene,toluene,ethylbenzene,and xylene(BTEX)vapor.Notably,sensing results toward toluene vapor in different relative humidities indicates that this superhydrophobic polymer has favorable toluene/water selective detection performance.Besides,the limit of detection toward toluene is lower than 1 ppm.

Spider diversity in Fanjing Mountain Nature Reserve, Guizhou, China, Ⅱ： Clubionidae(Araneae)

Totally fourteen species of Clubionidae are reported from the Fanjing Mountain Nature Reserve in this paper, including six species as new to science, namely, Clubiona corrugata B？senberg ＆ Strand, 1906（♂♀）, C. dichotoma Wang, Chen ＆ Zhang ZS, sp. nov.（♂♀）, C. fanjingshan Wang, Chen ＆ Zhang ZS, sp. nov.（♂）, C. globosa Wang, Chen ＆ Zhang ZS, sp. nov.（♂♀）, C. grucollaris Yu, Zhang ＆ Chen, 2017, C. huiming Wang, Zhang F ＆ Zhang ZS, sp. nov.（♂）, C. japonicola B？senberg ＆ Strand, 1906（♂♀）, C. jucunda（Karsch, 1878）（♂♀）, C. manshanensis Zhu ＆ An, 1988（♂♀）, C. pterogona Yang, Song ＆ Zhu, 2003（♀）, C. subapplanata Wang, Chen ＆ Zhang ZS, sp. nov.（♂♀）, C. subcylindrata Wang, Chen ＆ Zhang ZS, sp. nov.（♂♀）, C. subrostrata Zhang ＆ Hu, 1991（♂♀） and Pristidia ramosa Yu, Sun ＆ Zhang, 2012（♀）. All species are described or redescribed, and photoed, except Clubiona grucollaris Yu, Zhang ＆ Chen, 2017. Drawings of all new species are also provided.

Review of the wolf spiders from Hainan Island,China(Araneae:Lycosidae)

Twenty-eight species in 14 genera of the family Lycosidae Sundevall,1833 are documented from Hainan Island,China,including five new species:Allotrochosina huangi Wang,Li&Zhang,sp.nov.(♂♀),Al.limu Wang,Li&Zhang,sp.nov.(♂),Arctosa hainan Wang,Li&Zhang,sp.nov.(♂♀),Ar.tangguoi Wang,Li&Zhang,sp.nov.(♂)and Zoica hainan Wang,Li&Zhang,sp.nov.(♂♀).Eight new synonyms are proposed:Arctosa danzhounensis Barrion,Barrion-Dupo&Heong,2012 syn.nov.=Ar.springiosa Yin,Wang,Xie&Peng,1993;Hippasa sinsiloides Barrion,Barrion-Dupo&Heong,2012 syn.nov.=H.holmerae Thorell,1895;Lycosa hawigvittata Barrion,Barrion-Dupo&Heong,2012 syn.nov.=L.vittata Yin,Bao&Zhang,1995;Pardosa daxiansongi Barrion,Barrion-Dupo&Heong,2012 syn.nov.=P.pusiola(Thorell,1891);P.tieshinglii Barrion,Barrion-Dupo&Heong,2012 syn.nov.=P.sumatrana(Thorell,1890);P.villarealae Barrion,Barrion-Dupo&Heong,2012 syn.nov.=P.sumatrana(Thorell,1890);Pirata sanya Barrion,Barrion-Dupo&Heong,2012 syn.nov.=Lysania pygmaea Thorell,1890;Pirata catindigae Barrion,Barrion-Dupo&Heong,2012 syn.nov.=Pi.subpiratica(Bösenberg&Strand,1906).The genus Allotrochosina Roewer,1960 and the species Wadicosa okinawensis(Tanaka,1985)are newly recorded from China,and Pardosa aciculifera Chen,Song&Li,2001 is recorded from Thailand for the first time.Females of Arctosa tridentata Chen&Song,1999 and Ocyale qiongzhongensis Yin&Peng,1997 are described for the first time.Morphological illustrations and photos of all species are given.