Secondly , true taixial test by load in three different principal stress direction for study on soil anisotropic deformation characteristic are processed . lateral deformation relative to load direction , lateral deformation relative to lateral direction and the stess - strain relationship in load direction are analyzed , and soil anisotropic deformation characteristic on the three aspects of elastic ratio , poisson " s ratio and the property of compliment matrix are completely analyzed too 其次，为揭示土体各向异性变形特性，有针对性进行了三主应力分别单向加荷的真三轴试验研究，分析相对于加荷向的侧向变形、互为侧向的侧向变形、不同主应力加荷向的应力应变关系各向异性性状。
Research shows that four factors have great influence on the formation of complex rock mass . first , rock mass subjected six times of tectonic movement during long period of geo - history , each tectonic movement produced fractures and associated joints corresponding to the orientation of maximum principal stress and deteriorated the properties of fractures formed at former period ( s ) . second , down - cutting of langcangjiang river produced unloading fractures 采用了四种岩体质量分级评价方案对研究区岩体质量进行了研究，这四种方案包括：工程岩体分级标准( gb50218 - 94 ) 、水利水电围岩工程地质分类( gb50267 ? 99 ) 、岩体rmr分类( bieniawski , 1973 ) 、岩体质量指数z分级(小湾, 1995 ) 。
A material nonlinear finite element analysis for the cast - in - place reinforced concrete hollow slab that occurs from initial loading , cracking , yielding to failing is carried on . the cracking load , ultimate load , the displacement rules and the principal stress distribution rules of the hollow slab under the vertical loads are obtained . a material nonlinear finite element analysis for the single span hollow flat - plate floor is also carried on 其次对空心板进行了从加荷、开裂、屈服直至破坏的全过程材料非线性有限元计算，得到了空心板在竖向荷载作用下的开裂荷载、极限荷载及位移和应力分布规律；还对单跨无梁楼盖进行了材料非线性有限元计算，通过分析主应力场明确了柱上暗扁梁的作用；有限元计算的结果验证了以上的理论分析并得到了一些重要的结论，对改进现浇空心板无梁楼盖的构造措施有重要的参考价值。
Depending on how the ground surface is denuded , the feature of the current crustal stress field and rock stress environment can be calculated analyzing the result in this paper : by analyzing the recovering feature of the elastic deformation of the rockmass in unload - stage under various pressures , it has been found there is close relationship between the recovering degree of the elastic deformation of the rockmass and the unloading degree of the pressure the direction of the major principal stress in the crustal stress field is not consistent with the direction of the crushing stress regional tectonics borne during the last tectonic movement . the evolving degree of the regional geomorphology evidently affects the current crustal stress field , which changes from the self - weight stress field to the horizontal stress field , with the changing of the eroding degree of the regional geomorphology ranging from valley area to hilly country to flat country . in valley area , where there is two stress belts , the bankslope s tress belt and the self - weight stress belt within the mountain . the direction of the major principal stress is nearly parallel to the ground surface and inclines towards the valley in the bankslope stress belt . it is nearly vertical in the self - weight stress belt 通过本文的研究成果，根据区域性地貌的演化特征，我们可以大致地对现今地应力场进行判断：在分级卸荷条件下，岩体中弹性变形的恢复具有明显的规律性，这种规律对于研究地应力场的演变是有帮助的；地应力场中最大主应力方向与区域构造形迹在最近的构造运动中所受区域性挤压应力的方向无明显的对应性；区域性地貌形态的演化程度对现今地应力场的特征具明显的影响，随着区域性地貌侵蚀程度由峡谷区、丘陵区、平原区的变化，现今地应力场特征由自重应力场、水平应力场为主含少量自重应力场特征向水平应力场的规律变化；在峡谷区，山体中具有两个应力带：自重应力带和卸荷应力带，最大主应力方向在卸荷应力带中近平行于坡面并倾向于河谷、在自重应力带中近于直立；根据原始地面遭剥蚀的程度，可以大致地估算最大主应力和中间主应力的量值和方向；在丘陵区和平原区，最大主应力的方向近于水平，并与附近区域性侵蚀盆地和河流的展布方向基本平行，根据原始地面遭剥蚀的程度，可以大致估算其最大主应力的量值；根据区域性地貌形态的特征来分析工程区的现今地应力场特征，并进而大致了解岩石的应力环境，这种分析方法得出的结论与许多实际的地应力测试成果基本一致，对于大型水电工程地下厂房和压力隧洞的设计是有所帮助的。
The surface of natural fracture ( crack ) is parallel to the orientation of maximum principal stress . the principle orientation of anisotropic permeability reservoirs agrees with the orientation of the maximum principle stress . many engineering problems ( e . g . bore - hole stability , casing deformation failure during drilling , reasonable arrangement of wells , the optimum design of hydraulic fracture and so on ) are influenced by the in - situ stress orientation 天然裂缝面和裂隙面与最大主应力方向平行；在各向异性低渗透率油田中主渗透率方向与最大水平主应力方向趋向一致：在钻井过程中井壁稳定性，套管变形和损坏，油田开发井网合理布置、水力压裂优化设计等都与地应力方向有关。
The principal stress value arised alteration , the magnitude of stress closed to 25 ~ 32mpa , its influence scope was within the scope outside of tunnel opening 10 ~ 15 meter , maximum tense focused at vault and middle of floor about half meter . shearing stress focused at corner of vault and wall , always been sheared 主应力量值也发生了较大改变，压应力可达25 32mpa ，其影响范围在隧道边墙外10 15m ；拉应力集中在拱顶和底板中部约0 . 5m范围内，最大可达10mpa ；在拱腰和墙脚常为剪应力集中区，易发生塑性剪切破坏。
The formulas of the critical edge load and the critical load are wildly used in the definition of the bearing capacity in practice . for the ignorance of the middle principal stress , the results of the formulas of the critical edge load and critical load which are based on the mohr - coulomb strength criterion in the two - dimensional stress state tend to be conservative 临塑荷载、临界荷载计算公式一直是工程实际中计算地基承载力的理论基础，但是基于二维应力状态下莫尔?库仑强度准则的临塑荷载、临界荷载公式因为没有考虑到中主应力在强度上的有利作用而使计算结果偏于保守。
Three different aspects of anisotropic deformation including lateral strain , relative proportional relation of lateral strain and strain in load direction , and train increment induced by unit stress increment in load direction will be delicately analyzed . the stress strain relationship in different principal stress load direction can be reflected in the anisotropy of tangent elastic ratio or strain increment in load direction induced by unit stress increment in load direction 侧向变形可以从侧向应变、侧向应变与加荷向应变之间的相对比例关系或侧膨胀系数以及加荷向单位应力增量所引起的侧向应变增量三个不同方面深入细致地分析研究；不同主应力加荷向的应力应变关系各向异性可以反映在切线弹模以及加荷向单位应力增量引起的加荷向应变增量的差异中。
The computation results show that after reinforcing the soft and weak floor , the deformation of the surrounding rock of sides gets smaller , especially , that in the lower part of the sides decreases to a larger extent ; the size of plastic zones and the scope of strength - softening region in surrounding rock of sides become smaller ; the area that has an increase in the maximal principal stress in surrounding rock of sides shrinks , and the zones of peak - value of maximal principal stress approach the periphery of roadway 计算结果表明，加固软弱底板后巷道两帮围岩变形量减小，尤其是巷道两帮下部围岩变形量减小幅度较大，两帮围岩塑性区范围和软化区范围缩小，两帮围岩主应力升高区范围缩小，主应力峰值区域更加靠近巷道周边。
With the increase of lateral pressure modulus , the magnitude of principal stress decreases and the direction of it is hardly changeable ; with the increase of the angle between the direction of the maximal horizontal principal stress on magnitude and the fault bearing , the magnitude of principal stress increase and its direction can hardly change ; with the increase of the elastic modulus of rocks , the magnitude of principal stress increases and the direction changes more ; with the increase of pr , the magnitude of principal stress decreases and the direction changes more ; with the increase of lateral pressure modulus , the principal stress at hance , the tress at topmost arch , bottom arch and principal stress at lateral arch decreases , with the increase of the depth of tunnel , the stress of surrounding rock also increases , and the poorer the quality of surrounding rock is , the little its principle stress is 分析得出，随着侧压力系数的增大，主应力量值减小，主应力方位难改变；随着与断层走向的夹角增大，主应力量值增大，应力方向难改变：随着岩石的弹性模量的增大，主应力量值增大，方向变化越大；随着泊松比的增大，主应力量值减小，方位变化越大。随着侧压力系数的增大，顶、底拱处的各应力值增大，拱腰处的主应力减小，剪应力增大，侧拱处的各主应力减小，同一侧压力系数的条件下围岩质量越差，各应力值也越小；随着洞室埋深的增加，围岩压力也增大，围岩质量越差，其应力值也减小。
