With the double difference location method 1 676 earthquakes occured in the Three Gorges reservoir area(30.5°-31.5°N,109.5°-111.5°E),and recorded by Sanxia Earthquake Network from May19,2003 to Aug.2005 had been relocated.

The value of ecosystem service in the Three Gorges Reservoir Area will be reduced to 8852.90×104~9708.35×104 Yuan after the construction of the Three-Gorges Project.

Bernese GPS Software 4.2 is used to analyze GPS data from six repeated surveys occupied by the GPS network of the Three Gorges Reservoir Induced Earthquake Monitoring System from 1998 to 2003.The result shows that the crustal deformation in the Three Gorges Reservoir area is less active with a marginally measurable rate of 0 and 3 mm/a(±0.1～ ±2.0mm/a) with respect to stable South China.

By using the historical data of the Three Gorges Reservoir (TGR), a flood forecasting model for TGR intervening basin was proposed and established, with which the quantitative precipitation predicted data was coupled to study the influence of flood forecasting accuracy.

Bernese GPS Software 4.2 is used to analyze GPS data from six repeated surveys occupied by the GPS network of the Three Gorges Reservoir Induced Earthquake Monitoring System from 1998 to 2003.The result shows that the crustal deformation in the Three Gorges Reservoir area is less active with a marginally measurable rate of 0 and 3 mm/a(±0.1～ ±2.0mm/a) with respect to stable South China.

In view of the characteristic features of RIS in China, we can expect moderate earthquakes to be induced by the construction of the Three Gorges Project on the Yangtze River.

Social and Ecological Aspects of the Three Gorges Project

Current State of Construction of the Three Gorges Hydrosystem

Construction of navigation structures for the "Three Gorges" hydroproject

The design of the steel-reinforced concrete conduits is recommended for realization when constructing structure of the Three Gorges hydro development.

When the tall rigid frames for boat lefting in the Three Gorges were being analysed, we discovered that the so—called method of single distribution of moments can be improved upon as well as a new method of stress determination, namely the method of mean 'stiffness. For the calculation of tall frames, it was found that by means of lhese two methods accurate or approximate results can be obtained quickly and with great ease.In the case of the improved version of single distribution of moment method, a correction...

When the tall rigid frames for boat lefting in the Three Gorges were being analysed, we discovered that the so—called method of single distribution of moments can be improved upon as well as a new method of stress determination, namely the method of mean 'stiffness. For the calculation of tall frames, it was found that by means of lhese two methods accurate or approximate results can be obtained quickly and with great ease.In the case of the improved version of single distribution of moment method, a correction coefficient for the stiffness λ is to be used (λ_(AB)=1—C_(AB) C_(BA) μ_(BA), SO λ_(AB)=1—1/4μ_(BA), when the ordinary carrying factor is 1/2 and λ_(AB)=1—μ_(AB), when the oridnary carrying over factor is-1, where μ_(BA) is the ordinary distributing coeffcient). Multiplying the stiffness by this correction coeffcicnt, a set of distributing factors are calculated ( the same as those obtained by T. Y. Lin ). At the same, time, the ordinary carrying over factors are multiplied by the reciprocal of the correction coeffcient (?)/λ, so that a set of new carrying over factors are obtained. In this waY the calculation of new carrying over factors is much simplifted, at the same time the process of single distribution is also much simplified.In the case of the method of mean stiffness, an unsymmetrical multi-—story singlespanned rigid frame is transformed into a symmetrical one by using the mean stiffness instead of those original ones the structure. In this way the frame can then be analysed by means of Shagin (?) basic members and a single distribution with constant shears is crrried out. After this with a few ( once or twice ) simple adjustments, highly accurate results are ensued. This method can also been used for non-symmetrical multi-story and multi-spanned rigid frames as well (?) Vierendecl girders, and will give results to any degree of aocuracy quickly.

Research in fluvial geomorphology in China during the past 30 years was mainly along the lines of valley geomorphology, channel geomorphology, estuaries and deltas. A great amount of systematic investigations has been carried out in the fields such as valley evolution history and features of Changjiang River(Yangtze River) and Huanghe River(Yellow River) and their relations with geology, climate, neotectonic movement, etc. Field evidence suggests that the course of Sanxia(the Three Gorges) of Changjiang...

Research in fluvial geomorphology in China during the past 30 years was mainly along the lines of valley geomorphology, channel geomorphology, estuaries and deltas. A great amount of systematic investigations has been carried out in the fields such as valley evolution history and features of Changjiang River(Yangtze River) and Huanghe River(Yellow River) and their relations with geology, climate, neotectonic movement, etc. Field evidence suggests that the course of Sanxia(the Three Gorges) of Changjiang were formed as early as at the end of the Cretaceous, and then the Yangtze valley was sharply cut down from the uplifting Exi planation surface, and took shape of a series of deep gorges into limestone strata. Investigations have also found that the upper reach of Jinsha River near Dengke once flowed southeastward into Yalong River. Recently the study of river valley geomorphology of the Xizang Plateau reveals that Yaluzangbu River is an antecedent river and that the Daguaiwan gorge in the east of it is neither an elbow ot capture nor a tributary flowing westward to join the Indus as were formerly taken to be. Research into channel geomorphology developed somewhat later, but has made rapid progress. A grade separation system has been put forward for the classification of channel patterns, and attentions given to the dynamic characteristics of the formation and evolution of channel patterns by using C_v(variation factor of the peak discharge) and ρo/ρp(the ratio of incoming sediment concentration to the sediment carrying capacity in a channel) as indexes to indicate the stabilities of different channel patterns and the mutual transformations among them. By analyzing many rivers with heavy sediment concentration, a wandering index has been derived. Rivers having the value of greater than 5 are called shifting and less than 2 unshifting. In the middle and lower Changjiang, the latest research of meanders and relatively stable channel patterns has had some results. Observations and simulation experiments con the fluvial processes of the channels above and below reservoirs reveal that the channel of Huanghe below Sanmenxia Reservoir, after baving been washed by clear water, still remains shifting for a long time, and the headward silting end of Weihe channel above the reservoir stretches out or draws back within a certain limit. The investigations of deltas point out that since the Quaternary the mouth of Changjiang has been extending southeastward and that there exist imbricate fossil deltas under the water. As for the Huanghe delta, it is evident that since the diversion of the river course in 1855, a new delta with an area of 5,450 km~2 has been built up. Penetrating research has also been made on the geomorphological features and processes of the evolution of Qiantang River. Field survey discovers that the main source of Changjiang is Tuotuo River rising in Geladandong snowberg, and that of Huanghe is Kariqiu River originating in Geshigeya Mountain of the Bayankala Mountains.

The first thing in the stability analysis of underground opennings is the determination of the deformation failure-movement type of rock masses. In this paper five main types of deformation failure-movement has been mentioned, according to different combinations of the four rock mechanics factors. Thus, primary appreciation of stability and selection of mechanical model for the rock mass can be made in design work. Some methods of stability analysis for rock mass composed of rock blocks has been discussed, referring...

The first thing in the stability analysis of underground opennings is the determination of the deformation failure-movement type of rock masses. In this paper five main types of deformation failure-movement has been mentioned, according to different combinations of the four rock mechanics factors. Thus, primary appreciation of stability and selection of mechanical model for the rock mass can be made in design work. Some methods of stability analysis for rock mass composed of rock blocks has been discussed, referring to the underground power station of The Three Gorges project as an example. Planes of discontinuity should be simplified according to their relative size to the dimensions of the cavity. The influence of the stress component along the axis of the cavity on the stability of rock blocks has been emphasized. In those cases when finite element method in three-dimensions can not be used, calculations may be carried out by two-dimensional finite element method in combination with the method of the whole space projection on equatorial plane. When the orientation of the axis of cavity is to be determined, not only the direction of the maximum in-situ stress but also the azimuth of planes of discontinuity should be considered.