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软硬互层岩体中预应力锚索的作用机制研究
Alternative TitleStudy on the mechanism of prestressed anchorage in soft and hard interbedded rock
陈颖骐
Subtype博士
Thesis Advisor王全才
2018
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword软硬互层岩体 预应力锚索 极限拉拔力 预应力损失 补偿张拉
Abstract软硬互层岩体在我国分布广,当其下伏发育有软垫层时,容易造成中、大型崩塌或滑坡,预应力锚索作为主要有效的防护措施,在红层地区也得到了广泛应用。目前预应力锚索作用机制研究均集中在将锚固体周围的岩体视为匀质岩体,而针对软硬互层岩体中的预应力锚索的研究却相对较少。基于以上问题,本文在总结前人在预应力锚索作用机制成果的基础上,开展了以下研究:1. 归纳总结层状岩体强度破坏准则层面倾角是判定层状岩体破坏类型的依据,根据层面倾角将层状岩体破坏分为沿层面滑动破坏与非沿层面滑动破坏,并对不同的破坏模型采用不同的强度准则,最终以实例进行验证,表明方法的合理性。2.推导了基于传递荷载下的复杂地层中预应力锚索侧阻力分布计算方法根据传递荷载理论,引入衰减因子,将预应力锚索离散为多个子锚固段,并定义第一界面传递荷载存在脱粘作用的负指数分布情况,得出软硬互层岩体中的拉力集中型锚索和压力型锚索的锚固解析方法,并将该方法与实例进行对比,表明了该方法的实用性。 3. 针对软硬互层岩体中预应力锚索的破裂面类型,提出了基于布置角的极限拉拔力计算方法根据前人锚索破裂面试验成果,提出了倾斜预应力锚索破裂面的单参数方程;将锚索与岩体层界面垂直线的倾角作为划分不同破裂面破坏依据,并对三种破坏模式下的预应力锚索极限拉拔力进行研究,引入锚索侧阻力分布均匀系数,通过实例进行验证并标明所提出计算方法更为合理。最终对三种不同破裂面条件下的软硬互层岩体极限拉拔力进行分析,得出锚索与岩体层界面垂直线的倾角是影响锚索极限拉拔力最重要的因素。4. 提出软硬互层岩体中预应力损失计算方法提出软硬互层岩体中预应力锚索预应力损失计算方法。采用Burgers非线性蠕变模型拟合砂岩的蠕变特性,将岩体的瞬时弹性变形和粘塑性变形分别进行层面角度变换,同时考虑节理面的蠕变变形,最终得出不同层面倾角下的层状岩体蠕变变形方程。将预应力锚索预应力损失分为两部分:锚索自由段与坡体的耦合作用,锚固段与围岩之间的作用采用厚壁圆筒理论,分别对两种条件下的预应力损失进行分析,得出软硬互层岩体中预应力锚索的预应力损失方程,通过实例验证表明,预应力锚索预应力短期损失主要来自于自由段,长期预应力损失来自锚固段。最后对软硬互层岩体中不同影响因素对预应力损失进行分析,砂泥岩层厚比例与锚索布置角是引起预应力损失的两大关键因素。5. 提出两种不同的预应力锚索检测、张拉补偿技术及一种新型锚头结构提出两种不同的预应力锚索检测、张拉补偿技术及一种新型锚头结构。针对不同预留长度的钢绞线,提出螺环型锚索预应力损失补偿张拉结构和卡瓦型锚索预应力损失补偿张拉结构,并将卡瓦型锚索预应力损失补偿张拉结构应用于二郎山1#滑坡灾后重建工程中。针对落石、地震作用对锚头的影响,设计了新型预应力锚头,并对其进行拉拔试验,表明新型锚头结构提供抗震及抗冲击能力。
Other AbstractThe soft and hard interbedded rock mass is widely distributed in our country. When there is soft cushion under the red bed rock mass, it is easy to cause large scale collapse or landslide, and the prestressed anchor cable as the main effective protection measure, has also been widely used in the red bed area. At present, the research on the action mechanism of prestressed anchor cable focused on the rock mass around the anchoring body and treated it as homogeneous rock mass, but the research on prestressed anchor cable in soft and hard interbedded rock mass is relatively few. So, based on the problems above, on the basis of summing up the previous achievements in the action mechanism of prestressed anchor cables, the following research is carried out in this paper:Induction and summary of strength failure criterion of layered rock massThe bedding dip angle is the basis for judging the failure type of layered rock mass. According to the bedding dip angle, the failure of layered rock mass can be divided into sliding failure and non-sliding failure along the bedding, and different strength criteria are adopted for different failure models. Finally, an example is given to verify the rationality of the method.2.The calculation method of collateral resistance distribution of prestressd anchorage cable in complex stratum based on transfer load is derivedAccording to the transfer load theory, the attenuation factor is introduced to discretize the prestressed anchor cable into several sub-anchoring segments, and the negative exponential distribution of the first interface transfer load is defined. The anchoring analytical method of tension concentrated anchor cable and pressure-type anchor cable in soft and hard interbedded rock mass is obtained, and the comparison between this method and an example shows the practicability of the method. 3. In view of the fracture surface type of prestressed anchor cable in soft and hard interbedded rock mass, a method for calculating the ultimate drawing force based on arrangement angle is proposed Based on the test results of the rupture surface of the cable by Former researchers, the one-parameter equation of the fracture bedding of the inclined prestressed cable is proposed. The dip angle of vertical line between anchor cable and rock mass layer is taken as the basis for dividing the failure of different fracture bedding, and the ultimate drawing force of prestressed anchor cable under three failure modes is studied, and the uniform coefficient of collateral resistance distribution on the side of anchor cable is introduced. The proposed calculation method is more reasonable to be verified by an example. Finally, the ultimate drawing force of soft and hard interbedded rock mass under three different fracture bedding conditions is analyzed. It is concluded that the inclination angle of vertical line between cable and rock layer is the most important factor affecting the ultimate drawing force of anchor cable.Proposed the calculation method of prestress loss in soft and hard interbedded rock massProposed the calculation method of prestress loss in soft and hard interbedded rock mass. And the Burgers nonlinear creep model is used to fit the creep characteristics of sandstone. The instantaneous elastic deformation and viscoplastic deformation of rock mass are transformed into bedding angle respectively, and the creep deformation of joint plane is considered. Finally, the creep deformation equations of layered rock mass with different dip angles are obtained. The prestressed loss of prestressed Anchorage cable is divided into two parts: the coupling action between the free section of the anchor cable and the slope body, the action between the anchoring section and the surrounding rock is based on the thick wall cylinder theory, and the prestress loss under the two conditions is analyzed respectively. The prestress loss equation of prestressed anchor cable in soft and hard interbedded rock mass is obtained. The instantaneous prestressed loss of prestressed anchorage cable mainly comes from the free section, and the long-time prestressed loss of prestressed anchorage cable mainly comes from the anchoring section. Finally, the prestress loss of soft and hard interbedded rock mass is analyzed. The ratio of sand and mudstone layer thickness to the angle of anchor cable arrangement is the two key factors that cause the prestress loss.5.Two kinds of prestressed cable testing, tensioning compensation technique and a new type of anchor head structure are proposedTwo kinds of prestressed cable testing, tensioning compensation technique and a new type of anchor head structure are proposed. The prestress loss compensation tensioning structure of screw ring type anchor cable and the cable prestressing loss compensation tensioning structure of Kava type anchor cable are put forward, and the compensatory tensioning structure of prestress loss of kava type anchor cable is applied to 1#landslide reconstruction project in Erlang mountain, China. 
Pages158
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24780
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
陈颖骐. 软硬互层岩体中预应力锚索的作用机制研究[D]. 北京. 中国科学院大学,2018.
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