不同温度循环作用后大理岩细观损伤特征的定量研究

通过单轴压缩试验和细观损伤特征量化试验,对经历20、100、300、450、600 ℃五种温度循环后的四川锦屏大理岩试样的宏观力学性质及相应的细观损伤特征进行了研究。试验结果表明:① 经历不同温度循环的大理岩单轴压缩破坏试样的细观尺度微裂纹主要由沿晶裂纹、穿晶裂纹及晶内裂纹组成,且裂纹相应的基本几何信息服从广义极限统计分布特征;② 由于试样中的沿晶裂纹和穿晶裂纹的100 ℃温度阈值特征,致使宏观尺度的大理岩试样在温度100 ℃前后表现出不同力学性质;③ 沿晶裂纹是在经历温度循环后大理岩试样单轴压缩破坏中起主导作用的微裂纹,穿晶裂纹有一定贡献,而晶内裂纹并未发挥显著作用。     

大理岩三轴压缩破坏的能量特征分析

岩石材料的变形和破坏与能量的变化密切相关。利用刚性伺服系统对大理岩岩样进行了系列三轴压缩试验,基于试验结果,对大理岩在加载过程中各阶段能量变化的具体数值进行了计算和整理,研究了能量变化在加载破坏各阶段分别与围压、应力、应变的内在联系。结果表明,初始围压的增大能够相当程度上提高岩样的破坏应变能。在既定围压下,岩样在弹性变形阶段的能量变化与偏应力和应变均成正线性关系。随着初始围压的增大,岩样所吸收的能量随偏应力变化的增长速率降低,随应变变化的增长速率加快。在三轴压缩过程中,岩样在弹性变形阶段所吸收的能量占总能量的比重较小,绝大部分能量耗散于岩样的屈服变形阶段;并且随着初始围压的增大,屈服变形阶段所吸收的能量占总能量的比重提高。     

考虑软弱夹层的含孔洞大理岩力学特性模拟分析

天然岩体中常含有孔洞和软弱夹层等缺陷,为研究含1条软弱夹层与中心孔洞的大理岩在单轴压缩作用下的破坏模式和力学特性,采用数值模拟软件RFPA2D对试样破裂过程进行了模拟。结果表明:软弱夹层的存在改变了大理岩试样的破坏模式,当软弱夹层强度比较低,厚度比较大时,软弱夹层下部的大理岩基本不出现破坏;当软弱夹层强度不变时,大理岩试样的峰值应力随着软弱夹层厚度的增加而减小,峰值应力对应的应变随着软弱夹层厚度的增加而增加;当软弱夹层厚度不变时,大理岩试样的峰值应力随着软弱夹层强度的增加而增加,峰值应力对应的应变随着软弱夹层强度的增加而减小。研究结果对比揭示了不同厚度和强度软弱夹层含孔洞大理岩的破坏模式和力学特性,可为软弱夹层上部建设的岩体工程失稳破坏提供一定的参考。     

云南华坪地区饰面石材资源特征及产业布局分析

华坪地区位于云南省西北部,毗邻四川省攀枝花市,该区饰面石材分布广泛,形成了以碳酸盐岩为主,碎屑岩和岩浆岩为辅的石材资源。本文从华坪地区石材资源开发和利用的背景及意义入手,重点介绍了华坪地区饰面石材矿产的资源特征、勘查开发利用现状,在此基础上分析了华坪地区未来石材产业布局,并对今后石材资源的开发利用提出了几点建议。研究结果表明,华坪地区饰面石材主要矿种为大理石、花岗石和装饰砂岩。大理石矿石量约2.7亿m3,有白、灰、黄、黑4个系列10个品种;花岗石矿石量约3亿m3,有暗紫红、灰2个系列2个品种;装饰砂岩矿石量约1.7亿m3,有暗红-紫红1个系列3个品种。该区矿石质量优良,装饰性能俱佳,可满足不同层次、不同喜好人群的需求。伴随区域经济高速发展和城镇化建设加快推进,该区石材产业市场潜力巨大,资源开发利用前景广阔,可打造以华坪为中心的滇西北省级"石材产业群",为地方经济发展提供产业支持。     

Simultaneous Detection and Repair of Wetting Defects in Superhydrophobic Coatings via Cassie–Wenzel Transitions of Liquid Marbles

Superhydrophobic materials that prevent unwanted liquid adhesion can easily lose this property because of limited mechanical durability despite topological/chemical control and/or robust material selection. Here, long‐lasting superhydrophobic coatings with a system to effectively detect and repair damaged areas with “liquid marble,” a droplet covered with hydrophobic nanoparticles, are reported. The particles prevent direct contact between the droplet and the substrate (Cassie state). However, they can adhere to the non‐superhydrophobic damaged area in response to the substrate wettability via an external force or an increase in liquid volume via penetration of the outer nanoparticle layer (Wenzel state). This Cassie–Wenzel transition thus induces self‐assembly of the nanoparticles onto the non‐superhydrophobic area in response to the wettability, restoring superhydrophobicity.     

锦屏二级水电站深埋完整大理岩破坏机制的断裂力学分析

针对锦屏二级水电站深埋完整大理岩拉张型板裂化破坏和剪切型破坏,从断裂力学的角度对其发生机制予以解释。断裂力学理论表明,岩石在足够大轴向力作用下,其内部微裂纹在发生摩擦滑动或剪切滑移和自相似扩展后进一步弯折扩展。隧洞开挖后洞壁围岩径向应力降低,切向应力增大。当径向应力为零时,弯折裂纹继续发展,围岩产生平行于洞壁的破裂面,即产生拉张型板裂化破坏;当洞壁围岩存在一定径向应力时,弯折裂纹停止扩展转化为剪切裂纹扩展,即围岩产生剪切型破坏。对锦屏二级水电站深埋完整大理岩破坏机制的分析,为类似深埋隧道工程围岩失稳破坏机理的解释具有一定借鉴作用。     

单组分建筑用石材硅酮密封胶的研制

以107硅橡胶为基胶,添加白炭黑、碳酸钙等补强填料,不添加任何增塑剂,研制了单组分湿气固化硅酮密封胶。探讨了填料的最佳配合比例。该密封胶对大理石无污染,并符合国家建筑用石材硅酮密封胶标准。     

Design of multi-scale textured surfaces for unconventional liquid harnessing

The ability to manipulate liquids in a loss-free and refined manner has long been anticipated, with applications in fields such as analytical chemistry, medical diagnosis, and droplet-based manufacturing. The challenge derives from the liquid/solid contacts, which incur spontaneous spreading, strong pinning, and substantial retention. The retention-proof interfaces, including superhydrophobic surfaces, lubricant-infused surfaces, and liquid marbles, mitigate these issues by respectively introducing air, lubricant, and particulate layers to isolate liquids from underlying solids. Assisted by these interfaces, contrastive physical/chemical designs and engineering methods are leveraged to unlock unparalleled liquid-control methods that are otherwise inaccessible. In this review, we focus on the application of retention-proof interfaces in three facets of manipulation: the aliquoting, grip, and transport of fluids. We discuss the key features, strategies and implementations, highlighting the fundamental physics and operation principles. For aliquoting, the cooperation between diminutive geometries and interfaces in partition droplets are examined. For the grip, we discuss the impact of micro-/nanotextures on adhesion behavior and highlight the mechanisms of switching the adhesive forces. For the transport, we review various engineering and functionalizing forms through which subtle driving forces are dexterously imposed on mobile droplets. The performance of different techniques is evaluated, and potential directions are proposed.     

铜制品表面仿大理石热着色工艺

介绍了一种仿大理石纹肌理的制作工艺,以常规铜工艺制品为素材,主要工序有预处理、着底色、仿大理石纹热着色、漆或蜡封闭保护.所制大理石纹肌理清晰逼真,可以呈现不同的装饰效果.     

Influence of Specimen Shape on the Indirect Tensile Strength of Transversely Isotropic Dionysos Marble Using the Three-Point Bending Test

Abstract:  This paper focuses on the investigation of the three-point bending tensile strength of Dionysos marble. Using the classical relationship obtained from the theory of elasticity, the effect of the span length, the thickness/width ratio and the orientation of the specimens in the indirect tensile strength were investigated. In total, 42 experiments were carried out, divided in three sets of specially designed beams. Finally, the calculated bending tensile strength is compared with the corresponding value obtained from Brazilian indirect tension as well as ring tests.