京沪高铁全风化石英二长岩路基填料无侧限动三轴试验研究

为降低工程成本,京沪高铁建设中就地取用了石英二长岩全风化物作为路基填筑。通过全风化石英二长岩的无侧限动三轴试验,采集分析了该类土样的应力应变及加载次数关系,计算并探讨回弹模量随加载次数的变化规律,以及含水率与破坏应变等临界参数的关系。结果表明该填料主要工程特性为:含水率越大,临界参数性能越差,破坏趋势出现的越早。在工程实践中通过严格控制填料含水率和物理改良,取得了良好的工程效果和经济效益。     

含崩解软岩红层材料路用工程特性试验研究

红层软岩成分复杂而且部分岩类具有崩解特性,导致其工程性质复杂和不稳定。对组成红层软岩的各种岩类进行的化学成分、物理性质、耐崩解性等试验表明:组成红层软岩的各种岩石化学成分、矿物含量、物理力学性质、水理性质等差异较大,因各种岩类混杂,工程中很难区别对待。通过对试验结果的深入分析,给出了崩解后红层软岩路用工程特性指标间的相互关系式,并指出完全崩解后的红层材料性质稳定,压实度达到95%的崩解后红层材料填筑体的物理力学指标可满足其作为路基填料的要求。某高速公路工程应用及现场试验和工后观测结果表明,经一定程序处理后的红层软岩可作为路基填料,若采取适当的施工工艺可大大缩短工期。     

膨胀土路基土质改良室内试验研究

利用实例介绍膨胀土的物理力学性质对工程稳定性的影响,通过试验研究,说明了膨胀土经过掺加石灰改良后其物理力学性质发生的改变能够满足铁路工程路基填料的技术要求.     

过湿土掺灰填料在随岳高速公路南段的应用

江汉平原由于其特殊的沉积原因 ,其可用作填料的表层硬壳层具有特殊的物理力学性质 ,对其进行研究是随岳高速公路南段公路勘察设计中不可或缺的部分 ,更是影响到随岳高速公路南段投资的关键性因素。本文根据过湿土掺灰试验成果 ,就过湿土填料性质改良问题作出概要性总结     

安徽膨胀土铁路路基填料改良试验的初步研究

指出膨胀土吸水膨胀、失水急剧收缩开裂的特性决定了其不能直接作为路基填料,必须进行改良,针对两条拟建的铁路,通过取土进行室内改良配比试验,分析了膨胀土和改良土的物理力学性质,确定了最佳改良配比,作为设计时的参考。     

黄土路基填料石灰改良试验研究

通过对郑西客运专线黄土填料石灰改良室内试验研究,研究在不同配合比的条件下,石灰改良黄土的物理力学性质,主要包括有击实特性、压缩特性、强度特性等的主要影响因素,结合高速铁路对路基强度和工后沉降的严格要求,为黄土地区客运专线路基填料石灰改良的可行性提供参考依据。     

某高速公路高液限土路用性能的试验研究

根据室内试验研究了高液限土的工程特性,并采用不同掺灰率进行高液限土的改良试验,研究其物理力学性质变化规律。试验结果表明,掺灰后的高液限土,其液塑性指数发生明显的降低,强度得到提高,压实度也较易达到标准,证明用石灰改良高液限土具有良好的效果,可以满足高液限土作为路基填料的标准,而且生石灰改良效果比熟石灰好。     

某高速公路高液限土路用性能的试验研究

根据室内试验研究了高液限土的工程特性,并采用不同掺灰率进行高液限土的改良试验,研究其物理力学性质变化规律。试验结果表明,掺灰后的高液限土,其液塑性指数发生明显的降低,强度得到提高,压实度也较易达到标准,证明用石灰改良高液限土具有良好的效果,可以满足高液限土作为路基填料的标准,而且生石灰改良效果比熟石灰好。     

强风化岩路基湿化变形机理分析

在对强风化岩填料进行矿物成份、物理力学性质和水理性质实验数据分析的基础上,通过试验路堤修筑、现场浸水载荷试验研究强风化岩湿化、软化对强度和变形的影响;利用直径D=75cm的大尺寸平板载荷试验研究填石路基的回弹模量,为路面结构设计提供参数;结合试验数据分析了强风化岩的湿化变形机理,指出其可以作为路基填料使用;鉴于石料湿化变形以及膨胀变形这一特点,建议做好路基的放排水设计。     

全风化千枚岩铁路路基填料适用性试验研究

通过矿物成分分析、化学成分分析、颗粒分析、界限含水率、自由膨胀率等试验对全风化千枚岩试样的物理化学和水理性质进行了系统分析,研究了其用于铁路路基填料的适用性。研究表明试验选取的全风化千枚岩为C3组填料,满足重载铁路基床以下路堤填料要求。     

云母石英片岩片理面力学特征试验研究

云母石英片岩的矿物成分和微观结构决定了其各向异性特征,通过铸体磨片和电镜扫描试验,获得了云母石英片岩的矿物组成和微观结构特征;通过三轴剪切试验,获得了微风化岩样片理面力学参数;通过强风化和中风化岩块的点荷载试验,结合强风化岩样的片理面剪切试验,得出了强风化和中风化岩样的片理面力学参数;按照材料力学理论,采用片理面力学参数计算得出岩样的最小单轴抗压强度,进而计算得出岩样的各向异性系数;以垂直片理面的抗压强度作为计算依据,计算得出岩样的风化系数,进而总结出岩样的各向异性系数与风化系数的关系,揭示了风化过程中片理面力学特征的变化规律。     

Can weathering improve the toughness of a fractured rock? A case study using the San Giacomo granite

The physical–mechanical behaviour of the weathered San Giacomo granite, Sardinia, has been investigated using a combination of physical–mechanical tests and microstructural analysis. Fieldwork and microscopy suggest a pervasive microfracture system developed on a pre-existing magmatic quartz anisotropy. Alteration indices, chemical analyses and mineralogy indicate that the yellow staining is produced by the circulation of oxygen-rich rainwater through microfractures in the rock, resulting in the oxidation of biotites. Apart from the obvious modification of the original grey colouring, the precipitation of Fe-oxides and hydroxides has welded fractures together, leading to the partial recovery of the physical–mechanical properties previously compromised due to microfracturing.     

A study of the weathering of the Bukit Timah granite Part B: Field and laboratory investigations

Field investigations consisting of surface seismic refraction and electrical resistivity surveys, drilling and downhole geophysical logging of the rock mass and of the residual soil indicate that the weathering of the Bukit Timah granite has been rapid and is primarily caused by chemical decomposition due to the tropical climate in Singapore. The granite is usually overlain by a thick layer of residual soil. Laboratory tests indicated a large reductions of the material strength, the modulus of elasticity, the rock mass quality and other mechanical properties of the weathered granite. Apart from the mechanical properties of the residual material and/or of the weathered granite rock, physical properties including density, water content, Atterberg's limits, grain size distribution, permeability, sonic velocity and electrical resistivity were also studied in order to assess the weathering grade and the weathering processes.     

粉石英硅酸钙板的生产技术

本文介绍了以天然风化粉石英生产硅酸钙板的技术 ,使用粉石英制造硅钙板 ,产品质量优良 ,基材强度有极大提高 ,且因粉石英质地极纯 ,成本较低 ,所以可降低硅酸钙板生产成本。     

高温后花岗岩能量及结构效应研究

利用MTS815电液伺服材料试验系统,研究了花岗岩在25℃～1000℃高温作用后的三轴压缩力学性能,基于D8 ADVANCE 型X射线衍射仪,研究了花岗岩经不同温度加热处理产物的物相特征。结果表明：①经历不同高温作用后,岩样三轴抗压强度、轴向峰值应变与围压呈非线性二次多项式增长关系,破坏应变能与围压呈线性增长关系。②岩样三轴抗压强度、破坏应变能随温度的升高先增大后减小,呈二次抛物线关系,400℃为最大值。③石英、长石、云母三者的最大衍射强度随温度的升高先增大后减小,400℃时达到最大,结合宏观力学试验,可以推断400℃为花岗岩的阀值温度。④石英在573℃发生由石英转变为石英的可逆反应;长石的差热曲线在700℃～900℃出现吸热谷,结构发生了由晶态向非晶态的相转变;在997℃时,云母矿物晶格破坏羟基逸出形成钠长石,这些因素共同作用使得岩样力学性能在400℃之后随着温度的升高而逐渐劣化。     

Deep weathering of a group of thick argillaceous limestone rocks near Three Gorges Reservoir,Central China

Rock mass characterization is one of the most basic and important tasks in rock mechanics and engineering. Literature review indicates that although there are many publications available on weathered rocks, there are few reports in English on weathered argillaceous limestone rocks and their chemical and mechanical properties. This paper presents a case study of characterizing a group of highly weathered thick argillaceous limestone rocks. Most importantly, they can be easily and quickly decomposed into soils after they are exposed due to excavation. Consequently, they would substantially lose their mechanical strengths. Geohazards such as landslides and sinkholes could occur in uncovered highly weathered argillaceous limestone rocks. The problematic weathered rocks were found during the development of a new town in upper mountains above the Three Gorges Reservoir on Yangtze River in Central China in the past 20 years. The factual data are presented on the changes of chemical compositions and mechanical properties of the weathered argillaceous limestone rocks due to chemical weathering. Some empirical correlations are given to quantify the changes in their uniaxial compressive strength and deformation moduli in terms of their contents of calcium carbonate. The data and findings presented in the paper can be useful to future urban development in geologically poor mountainous environments occupied by highly weathered argillaceous limestone rocks in the world.     

风化土料修建高坝的可行性

本文以自然混合料和一种人工掺配料为代表,简单介绍了龙滩水电站工程风化土料现场碾压试验的部份成果。通过对风化土料力学性质、特别是强度特性的分析,说明风化土料属于砾石土范围,力学性质能满足填筑高土石坝的要求,是一种良好的筑坝材料。建议用指数方程表示抗剪强度,在稳定分析中指数方程的参数可以换算为c,（?）值。     

厦门海底隧道强风化花岗岩力学特性研究

 厦门海底隧道海域隧道地段存在多处风化深槽,岩体主要为全、强风化花岗岩。由于该类岩石强度低,压缩性高,自稳和自承能力差,在隧道衬砌结构的设计和施工工艺的选择方面会遇到一系列特殊的问题。主要通过对天然和重塑强风化花岗岩岩样进行一系列的室内试验,在掌握其基本物理力学特性的基础上,重点对其流固耦合作用下的力学特性进行研究,并建立该类强风化花岗岩的力学模型,通过反演分析对力学模型进行验证。研究成果对风化花岗岩类工程的力学参数取值有重要借鉴意义,对该类岩体中隧道的设计施工具有指导作用。     

Petrophysical properties and durability of granites employed as building stone: a comprehensive evaluation

The use of a rock as a building stone is conditioned by several factors, from its aesthetic characteristics to its petrophysical properties. Even though the latter are taken into consideration, only a few of them are usually assessed. The purpose of this study is to carry out a comprehensive evaluation of the petrophysical properties of nine Portuguese granites employed as dimension stones. Granites with different textural characteristics and degrees of weathering were selected in order to highlight the relationships between the properties, and to identify the most important ones affecting the rock behaviour. The post-tectonic granites, with low porosity and fewer fissures, show better mechanical behaviour, while the most weathered granites have poor mechanical behaviour that limits their use in some applications and/or environmental conditions.     

肯尼亚中风化响岩骨料对混凝土性能的影响研究

针对肯尼亚中风化响岩技术指标不良的现状,通过对拌合物性能、力学性能、电通量和氯离子渗透系数等的测试,研究了中风化响岩对混凝土性能的影响.结果显示:采用肯尼亚中风化响岩配制的混凝土,在相同的配合比条件下,初始坍落度和扩展度均较普通石灰石骨料混凝土小,经时损失相对较大,抗压强度和弹性模量低,但是仍然满足一般工程对混凝土力学...