Effect of rod friction on vane shear tests in very soft organic harbour mud     

Benjamin F. Schlue  Tobias Mörz  Stefan Kreiter 《Acta Geotechnica》2007,2(4):281-289

Very soft organic harbour mud is increasingly used as a filling and construction material in harbour construction and reorganization. The undrained shear strength of such soft sediments is the critical geotechnical soil parameter with regard to any specific construction design. Field and laboratory vane shear testing is a standard method to quickly determine this important parameter. So far, the effect of rod friction on vane shear tests in very soft organic soils is unclear. In this study we present results from laboratory experiments on harbour mud from a construction site in northern Germany. Relations among vane and rod geometry, penetration depth, water content, rod friction and undrained shear strength are derived. Based on these relations the influence of rod friction on vane shear test results is investigated. The results indicate that field and laboratory vane shear test measurements may be significantly influenced by rod friction. Methods are proposed to correct for the rod influence, which is shown to increase with rising water contents.  相似文献   

Collapse of caves at shallow depth in Gaziantep city center,Turkey: a case study     

Hanifi Canakci 《Environmental Geology》2007,53(4):915-922

This paper focuses on an investigation of the possible causes for the collapse of limestone caves in Gaziantep, Turkey. The city contains a lot of man-made caves, at a shallow depth, of various width and length. These caves were mainly excavated to provide work or storage space. As the city has been growing fast with increased population, many structures were constructed over these caves. Recently, two caves collapsed and five houses were damaged. These caves are all made of limestone and it was observed after the collapse that the limestone was saturated with water due to sewer pipe leakage and surface water. Tests were carried out on the limestone and it was determined that the compressive strength of limestone decreases by about 50% and the tensile strength decreased by about 80% when saturated with water. It was concluded that the reduced strength of the limestone combined with additional loads due to the factors mentioned above seem to be the main reason for these collapses.  相似文献   

Calibration of the high-pressure cohesive strength meter (CSM)     

S. Vardy  J.E. Saunders  T.J. Tolhurst  P.A. Davies  D.M. Paterson 《Continental Shelf Research》2007

Coastal erosion is an immense economic and social problem that has been receiving increased attention in recent years. A number of devices have been developed to determine the sediment stability in coastal areas: laboratory and field flumes; a range of different erosion devices; shear vanes and fall cone penetrometers. The cohesive strength meter (CSM) erosion device was developed to determine in situ the temporal and spatial variations in the erosion threshold of muddy intertidal sediments. Technological developments have enabled considerable improvements to be made to the original design over the last 15 years.  相似文献   

In situ measurements of surficial mud strength: A new vane tester suitable for soft intertidal muds     

P. Bassoullet  P. Le Hir 《Continental Shelf Research》2007

A vane fitted to a standard shear vane tester is described, the purpose of which is to obtain better measurements of the rheological properties of soft, surficial, intertidal muds (and consequently, variations in their erodability). Specifications and geometry of this vane are presented. The computation procedure is detailed, so that the methodology can be applied to any vane tester. The main improvement is a greater vertical resolution, typically less than 1 cm. Sets of direct measurements with this equipment and correlation with dry densities for three intertidal mudflats (estuaries and bay) are presented.  相似文献   

水泥—丙烯酸盐复合浆液的实验性研究   总被引：5，自引：1，他引：5  

胡安兵  刘雪松等 《地质与勘探》2002,38(3):93-95

水泥-丙烯酸盐复合浆液是在丙烯酸盐浆液的基础上研制出来的一种复合浆液，它既保留了丙烯酸盐浆液流动性好，固结体弹性好的优点，又大幅度地提高了浆液的抗压强度和粘结强度，因此在注浆时可以带来良好的综合灌注效果，还对复合浆液的粘度和强度进行了试验性研究。  相似文献   

DUT-1合成模型冰的弯曲强度和弹性模量实验分析   总被引：3，自引：0，他引：3       下载免费PDF全文

李志军  王永学  李广伟 《水科学进展》2002,13(3):292-297

依据渤海海冰物理和力学特征值和国内水池实验室能力,以1:10～1:30比尺要求,发展了DUT-1合成模型冰.文中简介该模型冰的理想参数、成分和制备过程.就其弯曲强度和弹性模量进行系统的实验分析.通过500多次弯曲实验,获得该模型冰在不同加载速度下的破坏方式,各向同性证据和弯曲强度为35～65kPa和弹性模量平均53MPa的结果.并且得到弯曲强度和弹性模量在实测湿密度范围内呈递增关系,浸水模型冰性能稳定时间超过4h,弹性模量与弯曲强度之比82%超过2000.  相似文献   

土钉支护弹塑性数值分析及稳定性探讨   总被引：12，自引：5，他引：12  

连镇营  韩国城  吕凯歌 《岩土力学》2002,23(1):85-89

用三维弹塑性有限元法对土钉支护进行了边开挖、边安装土钉和喷射混凝土面层的施工过程的数值模拟分析。通过一种强度折减技术探讨了土钉支护的稳定性。研究结果表明，施工过程中在不同的使用荷载作用下受力最大的土钉并不是一成不为的，因此，在土钉支护工程中不能随意地缩短某层土钉的长度。数值计算确定的潜在滑裂区和局部破坏区符合实际情况，认为钉体拔出是土钉支护最可能出现的内部失稳形式。  相似文献   

非饱和土的有效应力与抗剪强度   总被引：1，自引：1，他引：1  

王志玲  张印杰  丰土根 《岩土力学》2002,23(4):432-436

从孔隙土的存在状态出发，探讨了吸力的两种不同作用效果与非饱和形态的关系，从理论上论证了Bishop公式的正确性澄清了多年来一个基本概念上的误解。用新的观点阐述了非饱和土中抗剪强度分布不均匀及浸水湿陷的原因；同时还对Fredlund和卢肇钧提出的抗剪强度理论及参数的测试方法进行了分析，提出了各种抗剪强度理论在理论上都是相同的，其区别仅在于确定由吸力产生的那部分有效应力时采用的参数和测试 方法不同。为今后非饱和土的抗剪强度研究从理论转向实用提供了理论基础。  相似文献   

粘性土抗剪强度折算系数法的研究与应用          下载免费PDF全文

于清杨  詹军等 《地质与勘探》2001,37(5):85-87

系统介绍了粘性土抗剪强度的特征，并分析了其组成。在此基础上针对基抗支护设计中粘性土抗剪强度的取值问题，提出了采用折算系数法对抗剪强度C值进行处理，并利用此方法进行了长春光大银行基坑的支护设计，取得了良好的效果。  相似文献   

土工格栅加筋碎石土大型三轴试验研究   总被引：27，自引：6，他引：27  

赵川  周亦唐 《岩土力学》2001,22(4):419-422

在大型三轴仪上进行了素碎石土和加筋碎石土的三轴排水剪切试验，探讨了加筋碎石土的强度及变形特性；分析了塑料土工格栅的加筋机理，为加筋碎石土的理论计算提供了依据。  相似文献