Study On The Type Of Bank Collapse And The Interaction Between Soil And Water Of Mianhuatan Reservoir In Fujian

Mianhuatan reservoir is a large reservoir which is located in Shanghang county and Yongding county territory of longyan city in Fujian province.The main functions are power generation,including flood control,aquaculture,shipping and so on.The reservoir area belongs to subtropical Marine monsoon climate,and the wet season is clear.The groundwater of this area is mainly bedrock fissure water,tectonic crack water and pore water in the quaternary overburden.The pore watrer distributed in the rock fracture of granite,granodiorite and siltstone.Groundwater is recharged by rainfall and reservoir water,excreted to the reservoir or river.Reservoir of Mianhuatan reservoir is the mid-low mountains in areas of complex topography,terrain from the northwest to the southeast gradually reduced,Main structure form of the grounds in the area of low and medium denudation monadnock mountain denudation hilly topography,geomorphology,geology.The exposure strata of reservoir is relatively single,mainly for the former sinian system metamorphic volcanic clastic rock,cretaceous and Jurassic sedimentary rock,quaternary remnants of talus and pluvial form loose debris.Bedrock lithology is mainly for the granite,granodiorite,siltstone,loose quaternary overburden mainly for porosity than sandy soil.The earthquake peak acceleration in the reservoir area is 0.05 grams,the corresponding seismic basic intensity of to six level.The research object is the slope of Mianhuatan reservoir,the research goal is the reservoir bank collapse.The significance of the study is accurately predict the range of the reservoir bank collapse,ensure the safety of residents,transportation facilities and other projects on the bank.Research steps is field investigation,data access,laboratory test,data processing analysis,formula deduction.At present by graphic method to predict width of bank collapse is more,through the study of bank slope formula to predict the width and immature is less and immature.By studying the reproduce the horizontal development of cotton beach reservoir bank destruction process,according to the mechanism of interaction between soil and water conservation is deduced based on the water and soil balance formula of bank collapse prediction more accurate prediction of the reservoir bank collapse width.The technical route of this study is through the investigation and study specific natural and geological conditions,bank caving characteristics,bank collapse pattern,the factors influencing bank collapse,etc.Simulation experiments on the collapse of Mianhuatan reservoir in the indoor area,including the water level of bank collapse transverse broadening mechanism simulation and scheduling simulation test,the bank collapse transverse broadening mechanism simulation experiment is divided into a single large area of destruction and damage the bank slope under the lateral expanding mechanism simulation experiment.The formula of the collapse bank was derived by designing multi-factor orthogonal experiment,on the other hand,the prediction formula of the collapse bank based on soil and water balance is deduced which is according to he mechanism of soil and water interaction.This paper use the method of reference,simulation and derivation of formula.Research step is the first field field investigation,and access to relevant data,then carries on the related experiment indoors(bank collapse transverse broaden test,water level scheduling test,many factors test,single factor test),and then analysis formula is deduced based on the experiment of bank collapse,moreover the prediction formula of the collapse bank based on soil and water balance is deduced which is according to he mechanism of soil and water interaction,lastly,the typical profile validation is selected.Using a compass in the process of field investigation,the tape measure amount of measuring equipment,test in the process of using a tape measure,ruler,compass,etc.The experimental procedure adopts similar test,which is that the similarity of geometrical similarity,movement similarity and dynamic similarity,external condition and material composition are similar.This article main research results include eight aspects:(1)A field investigation of the collapse of the reservoir,during the period of 2014 to 2017,were investigated in both east and west in China,including Mianhuatan reservoir(Fu jian),Shuikou reservoir(Fu jian),Fuchunjiang reservoir(Zhejiang),Tankeng reservoir(Zhejiang),Xinanjiang reservoir(Zhejiang),Zhelin reservoir(Jiangxi),Longkaikou reservoir(jinsha river in Yunnan province),Heilongtang reservoir(Chengdu),Gongzui reservoir(Sichuan),Tongjiezi reservoir(Sichuan),Jinping 1 level reservoir(Sichuan),Baiyun reservoir(Hunan),Weixi reservoir(Hunan),a total of 14 mountainous reservoir.by investigating further understanding to the characteristics of the reservoir bank collapse,patterns,especially Mianhuatan reservoir has the characteristics of typical horizontal broaden the damage.and the profile of the 1-1 section of the Jinping 1 level reservoir is similar to that of the cotton beach.(2)By collecting long-term monitoring data of Longkaikou reservoir and Tankeng reservoir conttibute to the typical profile of the reservoir bank collapse prediction formula.(3)Correlation test,specific about reservoir bank collapse transverse broaden the simulation test of the process and mechanism of lateral(divided into single damage to broaden the simulation test and several damage simulation test of lateral broaden),the water level scheduling simulation test,single factor experiment and orthogonal factor experiment.(4)Through indoor simulated during cotton beach reservoir bank found to form local failure in local(vertical)on both sides of the transverse failure damage process of that,in accordance with field investigation is the basic.Failure rate of single local failure of bank collapse is more than a local failure of bank collapse transverse failure rate is slow,is mainly due to the failure of several local bank collapse has several breakdown point,and in several local failure through near the end of the part not well versed in the left three deforming toward right,will receive the left and right sides of the superposition of destruction,damage rate significantly faster.(5)Through the simulation experiments of reservoir scheduling,further understanding the influence of water dispatching of the reservoir bank collapse mechanism and the reason.Single factor experiment keep height(45 cm),bank slope gradient(40 °)and water level(30 cm),wave height(1 ~ 2 cm)unchanged,and change the single variable composition material-clay,medium sand,breccia type,coarse particle,explore composition influence on width of reservoir bank collapse.Multi-factor orthogonal experiment,through the four factors(material composition,bank slope,water level,wave height)three levels of orthogonal test,it is concluded that under the nine types of combination of width of bank collapse,contributing to the formula for the collapse of the interior test.(6)According to the result of four factors three levels orthogonal test,using the method of multiple regression bank collapse prediction formula is derived: S=2.5919e-2.886d(0.4189X1-0.2554X2+0.3348X3+14.3529X4)in type: S is the width of the reservoir bank collapse(m),X1 is bank slope angle(°),X2 is difference of water level(m),X3 stand for wave height(cm),X4 is nikon d60(mm),d is relative compactness.(7)On the basis of the mechanism of water and water interaction and the process of wave,the process of wave falling is based on the force equation of the vertical slope direction,contain foreshore R stress equation is deduced.Based on the value of R value,the formula of the prediction formula of the collapse bank based on the water and water balance was obtained:(8)Through prediction method based on the interaction between soil and water conservation,multivariate regression method,manual method,reservoir bank structure method,four methods for verification of the reservoir of the three beach pit profile and compare the results,the predicted results are more accurate based on water and soil balance.Due to soil and water balance of bank collapse prediction formula is in uniform sediment grain body and on the basis of cohesive sediment,there are some limitations.In addition,because the current reservoir monitoring data is less,available for verification of profile is less,need to further verify the applicability of the formula,and on a large number of repairing example with perfect this formula.