Research On Material Property Of Cemented Material Dam

The new type of dam namely Cement Material Dam(CMD)was put forward by the experts of China Institute of water Resource and Hydropower Research(IWHR)in 2009.This type of dam was proposed and developed from the concept and practice of Hardfill in Western country,Trapezoidal CSG in Japan,Cemented Sand Gravel and Rock(CSGR)Dam and Rockfill Concrete(RFC)dam in China,following the concepts of optimizing the dam structure to make better use of local materials and of selecting proper material for different parts of the dam in order to realize better function of structures.That is to make full use of the rapid rolling construction technology,and try to reduce the discarding material as much as possible.The concept of CMD covers the CSGR dam,the RFC dam or the Cemented Rockfill dam(CRD),and the Cemented Soil Dam(CSD),thus forming a continuous and complete material pedigree of darning.It has the advantages of safety,economic,environmental friendly and so on.It is a new type of eco-friendly dam construction technology,some temporary and permanent projects have been constructed in China.For further development of CMD,the following concepts should be investigated:(1)Preparation technology on diversification aggregate and material macro,mesoscopic performance;(2)High efficiency construction technology,equipment and quality control system;(3)Safety assessment and dam construction technology system throughout the lifespan.This paper is mainly based on the technology of the cemented material on diversification aggregate,focusing on the CSGR as the study object,carrying out innovative research around the cemented material and properties,preparation technology and quality testing.Some patens achieved in the study have been applied in projects.The main contents and achievements of this paper are as follows,(1)Mechanics and durability of CSGRThe problem of permeation and corrision of CSGR materials is studied.A new device for measuring permeability coefficient of CSGR is developed,which solves the problem of permeability coefficient measurement of core samples containing layers.The corrosion of Ca2+ in CSGR in long-term corrision is tested and verifIed by the new device.The in-situ shear parameters obtained from the study can provide data support for shear parameter design of CSGR dam.It was found that the compressive strength decreased by 7%?26%,the higher the compressive strength of the specimen and the smaller the effect of the low temperature water on the compressive strength,which provided a reference for the safe measure adopted for protecting the dam body during the winter time.The adiabatic temperature rise of CSGR is only about 10?,which greatly simplifies the requirement of temperature control during construction.(2)Quality inspection and construction method of CSGR materialThe quality inspection methods for the CSGR compaction and the treatment measures for the connection of external and internal part of CSGR dam is studied.In view of the problem that the quality inspection of the CSGR compaction is shown low efficiency of the water filling or sand filling method.The elastic wave technology is put forward and implemented to test the construction quality of the CSGR.Using the frequency dispersion characteristic of R wave,this study uses surface wave spectrum analysis(SASW)to determine the distribution of VR within the depth range below the surface of the paving layer of CSGR material,so as to characterize the quality of the rolling construction.According to the actual project,we get the wave speed threshold that represents the quality of roller compaction.The results of digging test agree with the elastic wave test,which proves that the accuracy of the detection.The SASW method can obtain the distribution of R wave velocity of the whole construction of CSGR,improve the detection speed and detection range of the CSGR compaction,and solve the problem of low quality detection efficiency of the CSGR compaction,which is suitable for large area detection of the CSGR dam.In view of the connection of external and internal part of CSGR dam is not easy to be compacted,a kind of grouting vibrating device has been invented,which could improved the construction quality,and has been applied to the Qianwei embankment project.The construction method of CSGR is put forward and applied.In view of the construction of CSGR dam lower than 30m,the construction technology of CSGR is put forward to solve the construction technical problems which the large rolling equipment can not be used.The results of the study is applied to Maomaohe dam in Leishan County of Guizhou Province.This is the first dam built in the world.With pouring method,the extension of the CSGR dam is widened.The mix proportion design parameters,strength design indexes and implementation methods of pouring CSGR are also obtained.(3)Preparation and construction technology of Cemented artificial sand and rock and Cemented soil for projectsThe technology of Cemented Artificial Sand and Rock(CASR)dam is put forward and applied to project.Based on CASR dam concept,the CASR construction technology is put forward and applied to Huayujing Dam in Xixiu County of Guizhou Province.This is the first dam built in the worldwide.A new crushing method suitable for CASR is proposed,which could solve the problem of aggregate preparation.The stone powder is used as the admixture to configure the CASR.The setting of water to binder,sand rate,air volume and stone powder dosage are also studied.Practice has proved that the cost of CASR dam can be decreased by 10%compared with the choice of RCC gravity dam.According to the dyke of Pangtoupao irrigationarea in Heilongjiang Province,this paper studies the use of local soil to make the cemented soil to build the embankment,and puts forward the cement content and preparation method,making the prepared cemented soil meet the requirements of corresponding design age of the compression strength and the anti-seepage grade.