《土的抗剪强度试验方法》由会员分享，可在线阅读，更多相关《土的抗剪强度试验方法（25页珍藏版）》请在金锄头文库上搜索。
1、土的抗剪强度 试验方法Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.一、室内试验二、野外试验抗剪强度试验直剪试验、三轴试验等制样（重塑土）或现场取样缺点：扰动优点：应力条件清楚，易重复十
2、字板扭剪试验旁压试验原位试验缺点：应力条件不易掌握优点：原状土的原位强度 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.直接剪切仪分为应变控制式和应力控制式两种，前者是等速推动试样产生位
3、移测定相应的剪应力， 后者则是对试件分级施加水平剪应力测定相应的位移 ，目前我国普遍采用的是应变控制式直剪仪。 一、直剪试验Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.土样Evalua
4、tion only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Cli
5、ent Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Pro
6、file 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.PAST = 100KPa = 200KPa = 300KPafOc1、试验原理与资料处理ff=ctan Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Cop
7、yright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.通过过控制剪切速率来近 似模拟拟排水条件1. 固结慢剪：施加正应力至充分固结，慢慢 施加剪应力：小于0.02mm/分， 以保证无超静孔压水 2. 固结快剪施加正应力充分固结在3-5分 钟内剪切破坏 3. 快剪（不排水剪）施加正应力后立即剪切3-5分钟 内剪切破坏PSTA2、试验分类6转/分钟慢剪 12转/分钟快剪Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Cli
8、ent Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.PSTA3、试验过程中的应力变化在加剪应应力以前，试试件处处于侧侧限状态态， 23 k 1加剪应应力后，主应应力的方向产产生偏转转，剪应应力愈大，偏转转 角也愈大，所以试验过试验过 程中主应应力的方向是不断交化的。在试验资试验资 料的分析中，假定试试件中的剪应应力均匀分布 ，但事实实上并非如
9、此。当试试件被剪破时时，靠近剪力盒 边缘边缘 的应变应变 最大，而试试件的中间间部分的应变应变 相对对要 小得多，剪切面附近的应变应变 又大于试试件顶顶部和底部的 应变应变 。所以，在剪切过过程中，特别别是在剪切破坏时时， 试试件内的应应力和应变应变 ，既非均匀又难难确定。 Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Co
10、pyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 直接剪切仪具有构造简单，操作方便等优点，但它存在若干 缺点，主要有： 剪切面限定在上下盒之间的平面，而不是沿土样最薄弱的 面剪切破坏； 剪切面上剪应力分布不均匀，土样剪切破坏时先从边缘开 始，在边缘发生应力集中现象； 在剪切过程中， 土样剪切面逐渐缩小，而在计算抗剪强度 时却是按土样的原截面积计算； 试验时不能严格控制排水条件，不能量测孔隙水压力、在 进行不排水剪切时，试件仍有可能排水，特别对于饱和粘性 土。 由于土的抗剪强度受排水条件的影响显著，故试验结果
11、不够 理想。但由于它具有的优点，故仍为一般工程广泛采用。4. 试验优缺点Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.l 设备简单，操作方便l 结果便于整理l 测试时间短优点 l 试样应
12、力状态复杂l 应变不均匀l 不能精确控制排水条件l 剪切面固定缺点PSTA类似试验：环剪试验单剪试验Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.试样压力室压力水排水管 阀门轴向加压杆有
13、机玻璃罩橡皮膜透水石顶帽二、 三轴剪切试验Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Asp
14、ose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Sli
15、des for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.应变控制式三轴仪：周围压力系统，轴向加压 系统，孔隙水压力量测系统组成 3 3 3 3 3 3试验过程： 先加周围压力 3 ； 然后施加轴向力1= 1-3 ，增大 1直到破坏。 分别做围压为100 kPa 、200 kPa 、300 kPa的三轴试验，得到破坏时 相应的1(一）试验过程Evaluation only.Evaluation only. Created with
16、Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd. 3 3 3 3 3 3 绘制三个破坏状态的摩尔应力圆， 画出它们的公切线抗剪强度包 线，得到强度指标 c 与 c(1-)f(1-)fEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client P
