| Tibet is a large province with abundant water resource in china, but because it is not enough to develop and utilize, the soil and water loss is very serious every year, the soil is poor, the kind of corps is single, the yield is poor, so in order to improve peasants' living standard and the yield of corps, it is urgent to develop and utilize the water resource reasonably. The Jiangxiong reservoir in Tibet is a typical example of the development and utilize of water resource. Jiangxiong reservoir lies in the boundaries of Gongga county of Shannan Prefecture of Tibet, Jiangxiong section of the upper of Langjiexiong River, from Gongga 33km, from Lhasa——Shannan Highway 17km. Langjiexiong River is a primary tributary of right bank of Brahmaputra middle, rise in Pubuzaiwei Mountains, total length 36km of principal river. The dam lies on the upper of Bana village Langjiexue country about 250m, The geographical position is east longitude 91o61ˊ, north latitude29o08ˊ. The dam is 3790m above sea level, the above drainage area of the dam si 154.17km2,River length 18.58km, river slope 47‰ , design high 33.66m of the dam, the dam roof total length 691.5m, total capacity 11,691,900m3, it is a medium reservoir for irrigation mainly, the dam type is the earth and stone dam, it is a third level permanent hydraulic structure.In Tibet, because it is,the traffic is inconvenient, especially the Quaternary stratum contains a lot of erratic boulder and huge stone, and the surface is incompact, so the hole is apt to collapse in drilling, the ordinary technology of drill is infeasible. The DTH drilling is feasible in technology, but because it is high-cold and anoxia, the air compressor can't work best, the drilling penetration rate is low. We adopted transient surface wave physics exploration technology in the exploration survey of Jiangxiong reservoir, on the base of several holes, we can get the accurate stratify of the strata, offer reliable geological parameter for the design, economize our time and fund.The rationale of Rayleigh wave exploration is that Rayleigh wave utilizes the kinematics characteristic of the wave, the more important is that it utilizes the dynamics characteristic of the wave too. As to the ordinary elastic wave, it utilizes the kinematics characteristic of the wave only, and the wave speed and wave resistance of different layer must be different, so Rayleigh wave can reflect the mediator more distinct.Under the condition of homogeneous medium, the wave length of Rayleigh is independent of the frequency of oscillation f, that is to say the transmission of Rayleigh wave doesn't have the dispersion character under the condition of homogeneous medium.Under the condition of layered medium, is the function of f, that is to say the transmission of Rayleigh wave has the dispersion character under the condition of layered medium. Through calculation we can get the rule of variation about horizon amplitude and vertical amplitude of Rayleigh wave and the depth of wave length. The rule indicate that when the depth z is half of, the majority power of Rayleigh have lost. When depth and wave length are equal, the power lost quickly. So we can consider the penetrate depth of Rayleigh is equal to the wave length. This illustrate that the wave speed of a certain wave length is mainly relative to the physical characteristics of stratum which depth is less than, this character offers the foundation of the superficial layer exploration by Rayleigh wave.We can know from, we can get curve and frequency dispersion curve form different wave length of Rayleigh wave and the corresponding frequency of elastic wave and the corresponding elastic wave speed. The character and variation rule of frequency dispersion curve is relative to the geological condition, so we can get the geological structure of certain depth region underground and Rayleigh wave speed of different depth through the inversion calculation of frequency dispersion curve.The exploration method utilizes transient surface w...
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