【作者】 赵宪民；

【导师】 赵法锁；

【作者基本信息】 长安大学 ， 地质工程， 2013， 博士

【摘要】 三河口水利枢纽为引汉济渭工程的两个水源之一，是整个调水工程的调蓄中枢。拱坝坝高145m，水库总库容为7.1亿m3，调节库容6.6亿m3。坝址区工程地质条件复杂，断裂及节理发育，对坝肩的稳定有一定的影响。可利用岩体为变质砂岩、结晶灰岩，局部夹大理岩、伟晶岩脉及石英岩脉，该类岩体主要为坚硬岩，但在纵波波速、力学参数上存在较大的波动性，根据现行规范在划分岩体结构、岩体风化及岩体质量方面与实际存在一定的偏差，划分结果不能真实反映岩体的工程地质特征，直接影响建基面的选择。如何准确评价建基岩体的特征，安全、经济的选择建基面的位置，以及根据选择的建基面进行坝肩稳定性的分析，成为该工程重要的研究课题。论文以三河口拱坝建基岩体为研究对象，重点开展建基岩体的结构、风化划分和岩体质量评价，在此基础上进行建基面的选择及坝肩稳定性分析研究，主要取得的成果如下：（1）开展了大量的岩体变形试验、直剪试验、波速测试、钻孔变形试验等现场原位试验，重点研究了变质砂岩、结晶灰岩的力学特性，获得了一系列岩体力学参数，建立了岩体变形模量与波速的关系。（2）通过区域断裂特征、震源机制解、地应力测试、有限元数值模拟等方法，确定该区最大主应力方位为NE向；根据坝址区横剖面应力场的数值模拟结果，把河谷应力场分为5个带，获得了每个应力分带的基本特征。（3）在对结构面发育特征进行分析的基础上，采用结构面间距、完整性系数、RQD等定量指标，结合水利水电工程地质勘察规范，提出了三河口拱坝坝址区岩体结构分类标准。根据坝址区岩体结构分类结果，中坝线岩体结构较上、下坝线更好。（4）利用纵波波速、波速比、完整性系数等定量指标，根据现行规范的规定，结合现场平硐的调查，对坝肩、坝基进行岩体风化程度的划分。划分结果表明右岸坝肩岩体风化程度整体高于左岸。（5）建立了以变形模量、纵波波速、完整性系数、岩体抗剪强度指标、岩体结构类型等为代表性指标的三河口建基岩体质量分级标准。采用BQ分级标准、《水利水电工程地质勘察规范》（2008）标准及本文分级标准对三河口坝址区岩体进行质量分类，分类结果表明本文分级标准更合理、经济。（6）采用拱梁分载法、有限元法对三河口拱坝拱端应力进行了分析，并选取控制性指标建立了三河口拱坝建基面选择的量化标准，最终确定了三河口拱坝建基面界限。（7）利用三维数值模拟计算分析了建基面上部岩体挖除后岩体的应力、变形特征，以及在基本荷载作用下坝肩的变形特征、应力特征及稳定情况。计算结果表明，在正常工程荷载作用下，坝肩岩体整体是稳定的。更多还原

【Abstract】 The Sanhekou Hydropower project,which is one of the water diversion from HanRiver to Wei River Project，s two water sources,is regulation center of the diversionproject.The height of arch dam is145m,the total reservoir capacity is710millionm3,and the regulating storage is60million m3.The engineering geological conditions indam site is complex,there grew fault and joints,it has certain influence on the stabilityof the dam abutment.Available rock mass is metamorphosed sandstone, crystallinelimestone, and locally inclusion are marble, pegmatite vein and quartz vein,this kind ofrock mass is mainly for hard rock,but there is a big volatility in the longitudinal wavevelocity and mechanical parameters,also,according to current codes there are certaindeviation with the reality on the division of rock mass structure,rock mass weatheringand rock mass quality. The result of the division cannot truly reflect the engineeringgeological characteristics of the rock mass, directly influence the choice of thefoundation interface. So the important research topic in the project is accuratelyevaluating the characteristics of the foundation rock,safely and economically choosingthe location of the foundation interface,and according to the selected foundationinterface taking dam abutment stability analysis.In this paper, we take Sanhekou arch dam foundation rock as the researchobject,focus on studying the complex rock structure,weathered divided and rock massquality evaluation.Based on these researches,we have taken the choice of the foundationinterface and analyzed the stability of arch dam abutment.The main research results areas follows:(1) In this paper, we have carried out a large number of rock mass deformationtests,direct shear tests,wave velocity tests and drilling deformation tests etc in-situ tests,focused on research that the mechanical properties of the metamorphic sandstone andthe crystalline limestone,obtained a series of rock mass mechanics parameters,asloestablish the relationship between rock mass deformation modulus and wave velocity.(2) Through regional fracture characteristics,focal mechanism solutions,geostressmeasurement,finite element method numerical analysis,we have determined the area ofmaximum principal stress orientation for the NE;According to the numerical simulationresults of the dam site cross section stress field,the valley stress field is divided intofive,the basic characteristics of each stress points are obtained.(3) On the basis of the analysis of structure plane development features,we haveadopted the discontinuity spacing, intact coefficient, RQD etc tangible criteriacombinedwith Code forengineering geological invcstigation of water resources and hydropower, weput forward that Sanhekou Arch Dam Area rock mass structure taxonomy.According tothe classification results of the dam site rock mass structure,the middlestream dam lineof rock mass axis structure is better than the upstream and the downstream dam axis.(4) In accordance with the regulation of current codes and longitudinal wavevelocity,wave velocity ratio,intact coefficient tangible criteria, and combined with sitetunnel survey, rock mass weathering of abutment and foundation are divided. The right bank abutment rock mass weathering degree as a whole is higher than the left bank.(5) This paper has established Sanhekou dam foundation rock mass quality gradingstandards, which take deformation modulus,the longitudinal wave velocity,intactnessindex,rock mass shear strength index,rock mass structure type as representativeindicators.Using BQ grading standard,《Code for water resources and hydropowerengineering geological investigation》(2008)standards and grading standards of thisarticle,we have taken a quality classification for Sanhekou dam area rock mass, theclassification results show that,the grading standards of this article is more reasonable,economic.(6) To analyse the Sanhekou arch dam arch spandrels stress by multi archcantilevermethod and finite element method.we have Selected controlling index, established thequantitative criteria of Sanhekou arch dam foundation surface selection,ultimatelydetermined Sanhekou arch dam foundation surface boundaries.(7) By using three-dimensional numerical simulation analysis,we have analysedrock mass stress and deformation characteristics after the base surface rock excavation,andanalysed stress and deformation characteristics of dam abutment and the stability. Theresults show that the dam abutment rock as a whole is stable,under normal loadcondition of the dam body resistance.更多还原