主应力

Experimental study of stress-strain relationship of normally consolidated intact soft clay in Hangzhou under undrained fixed shear of principal stress direction and monotonic rotation of principal stress axis had been done, which was used to reflect the soil properties response to the monotonic rotation of principal stress axis under real engineering conditions.

为反映真实工程条件下主应力轴旋转应力路径引起土体性状的变化，对杭州地区正常固结原状软黏土在固结不排水的主应力轴定向剪切和主应力轴单调旋转条件下的应力-应变关系进行试验研究。

The three groups were loaded and analyzed under the same loading according to the mean value of the bite force of incisors. RESULTS:(1)The maximum stress of dentin in group A was twice higher than that in group B. The maximum primary stress, minimum primary stress and maximum shear stress of group A were respectively 236.35, 228.83 and 218.05 percent of those in group B. The difference of maximum stress values of group B and group C was neglectable.(2) The maximum stress distribution of dentin in group A and group B was quite different (the stress was concentrated in labial and lingual side of the cervical dentin in group A, otherwise in group B it was concentrated in the area around the alveolar and the labial and lingual side of the dentin which was opposite to the tip of the cast metal post and core). The maximum stress distribution of dentin in group A and group B was almost the same.

结果：(1)从牙本质的应力大小来看，A组中牙本质最大应力值比B组中牙本质最大应力值增大了1倍以上（最大主应力、最小主应力和最大剪切应力A组分别是B组的236.35%、228.83%和218.05%），而B组与C组的牙本质最大应力值相差极小；(2)从牙本质的应力分布位置来看，A组与B组的牙本质最大应力分布位置相差甚远（A组主要集中在牙颈部唇舌侧肩台部的牙本质上，B组主要集中于牙槽嵴顶附近及铸造桩核尾端相对应的唇舌侧的牙本质上），而B组与C组的牙本质最大应力分布几乎在同一位置。

Based on the former study of soils constitutive relation involving principal stress axes rotation,the influences of principal stress axes rotation on the distribution of stress and deformation of soils are provided through numerical simulation of plane strain problems of soils involving rotation of principal stress axes.

在含主应力轴旋转的土体本构关系研究的基础上，通过含主应力轴旋转的土体平面应变问题的弹塑性数值模拟结果分析，总结主应力轴旋转对土体应力分布与变形影响的规律，得出需要考虑主应力轴旋转的条件及其影响的相对大小。

The plastic deformation induced due to cyclic rotation of principal stress axes alone can be in the same magnitude as that due to shear with fixed principal stress axes. 2 The volumetric strain due to shearing of cyclic rotation of principal stress axes is found to be composed of a reversible dilatancy component and an irreversible dilatancy component. The former is characterized by its reversibility and is independent of past shear history, the latter by its irreversibility increases with the increase of cycle number yet its increase rate decreases with its accumulation. 3 The obvious non-coaxiality between directions of the principal stresses and principal strain increments is found and its degree depends largely on the change of shear stress component. 4 The intermediate principal stress has considerable effects on the deformation behavior of sands in the condition of cyclic rotation of principal stress axes. The accumulation rate of the irreversible dilatancy component increases with the increase of the intermediate principal stress parameter.

具有初始各向异性的砂土在纯应力主轴循环旋转排水条件下的主要变形规律为：①纯应力主轴循环旋转可产生与应力主轴固定单调剪切处于同一数量级的塑性变形；②纯应力主轴循环旋转引起的剪切体变包含可逆性剪切体变分量和不可逆性剪切体变分量两部分，其中可逆性剪切体变分量在一周内可完全恢复，基本与应力历史无关；不可逆性剪切体变分量随循环周数的增加呈单调增加，且增加速率随其自身累积值的增大呈减小趋势；③应变增量主轴与应力主轴之间的非共轴现象显著，且在一周内具有分段性；④中主应力对应力主轴循环旋转条件下砂土的变形特性有重要影响，不可逆性剪切体变分量的累积速率随中主应力系数的增加而增加。

How to easily and reasonably determine the value of principal stress in the direction of plane strain is the key point.

基于弹塑性理论及土的试验规律，在平面应变的简单加载条件下，假定主应力之间的关系为双线性函数，并利用一维固结和破坏时的主应力状态，确定双线性函数的系数，得到平面应变方向上主应力计算公式的一个较合理形式，为应力状态和材料性质的函数。

The principal stress in the plane strain direction, which can be determined under the rigidity-plasticity assumption using static earth pressure coefficient , is the intermediate principal stress under the limit equilibrium condition. The relationship between major and minor principal stresses is obtained based on the strength criterion.

平面应变方向上的主应力在极限平衡条件下为中主应力，在刚塑性假定的基础上通过静止土压力系数确定，结合强度准则得到大主应力与小主应力之间的关系，进而求得土压力系数。

However, the pseudo-triaxial strengths of several rocks from the best fitting solutions have great scatterness from the real magnitudes. Also, it does not correspond to the experimental results that rock has the same strength under conventional triaxial compression and tension; the maximum increase of strength from intermediate principal stress has a linear relation with the minor principal stress; and the first-order derivative of strength has an interruption at the peak point.

此外，统一强度理论认为岩石三轴伸长强度与常规三轴压缩强度相同，在最小主应力恒定时中间主应力引起的强度最大增加值随最小主应力线性增加，且强度关于中间主应力的一阶导数在峰值点是不连续的，这些都与试验结果不能完全协调。

Firstly, the paper introduced the working principle and device of the two-pass grate-rotary kiln and had an analysis method of mechanics of the tyre. We have put forward the finite element analysis of the contact stress of the tyre-roller based on the whole construction mode of shell-kiln liner-large gear-tyre-roller of the rotary kiln and obtained the strength and distributing rule of the tyre's contact stress. The research shows that within one week the contact stress mainly lies in two leading peak value and catastrophe which appear at the contact zone of the tyre and supporting roller. Then we regarded the tyre's stress as the test of unknown plane stress of principal stress. Utilizing mature and modern testing technology, we raised the testing principle and scheme of tyre stress and then had a on-the-spot test of the stress. Comparing the analysis result of the test with the one calculated from the finite element analysis, it proofed the rationality of finite element analysis method of integral modeling and the correctness of the contact stress result of the tyre and roller. Finally, for two-pass of similar rotary kilns, using the ANSYS APDL re-development technology, carried on the re-development about the overall finite element analytic method of thecontact stress of tyre-roller.

首先，本文介绍了2档回转窑的工作原理和装置，对滚圈的力学行为进行了分析，提出了基于筒体-滚圈-托轮的回转窑整体建模的有限元分析法，来对滚圈-托轮的接触应力进行有限元分析与计算，得到了滚圈接触应力的大小和分布规律，并求得滚圈外中内圈节点的主应力；其次，把滚圈的受力看成是主应力未知的平面应力的测试，利用现代测试技术，提出了滚圈主应力测试的原理和方案，并对滚圈的主应力进行了现场测试，现场测试分析结果与有限元分析计算出的主应力相比较，证明了整体法建模的有限元分析方法的合理性和滚圈-托轮接触应力结果的正确性；最后，利用ANSYS的APDL的二次开发技术，针对2档同类回转窑，就滚圈-托轮接触应力的整体有限元分析法进行了二次开发。

The new method gives out a set of equations based on the fundamental algebra rules that principal stress trace obeys and the essential attributes it possess, we then combine these equations with further information described in this paper leading to an exact description of the conic representing the principal stress traces.

该方法是根据主应力迹线满足过任意三条等倾线的主应力都可以用二次曲线来描述这一条件，再利用主应力迹线本身所具有的性质列出方程组解算出描述主应力迹线的一元二次方程，然后根据方程描绘出所求的主应力迹线。

The measurement results show that the general characteristics of the present crustal stress field of the project area are as follows: the horizontal principal stress is the maximum principal stress, and the preferred orientation of the maximum horizontal principal stress is NW-WNW, the maximum principal stress of surrounding rocks of the plant buildings and high-pressure branch tunnel area is generally 14.5±0.5 MPa and the minimum principal stress is 9±0.5 MPa; the dead oad-bearing capacity of surrounding rocks is 10—14 MPa; and the surrounding rocks are essentially impermeable at high pressures of 8—10 MPa.

测量结果表明，工程区现今地壳应力场的总体特征为：水平主应力为最大主应力，最大水平主应力的优势方向为NW-NWW向；厂房和高压岔管区围岩的最大主应力值一般为14.5±0.5MPa，最小主应力值一般为9±0.5MPa；围岩自身的抗载强度一般为10～14MPa；在8～10MPa高压力作用下围岩基本不透水。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。