Traditional numerical models of flow are established in general on the basis of Saint-Venant equations for numerical soloution, the basic assumption of which is that the flow must be of continuity. Hence, it is extremely farfetched to apply the flow numerical model which is based on Saint-Venant equations to calculating the dam-bursting problem.

The authors present a new method of flow numerical simulation based on BGK Bolzmann equation for describing molecular motion, in which there is no assumption that the flow should be continuous. Calculations show that this numerical model can accurately and steadily simulate the problem of dam-bursting wave.

A new method is developed for the calcuation of hydraulics characteristics of dam-burst with arbitrary outlet which can be described with a number of broken lines. Combinative-parameters are defined firstly accor-ding to all parameters defining the cross-section of the outlet. A transformation related to the combinative-parameters is deduced thereafter. With this transformation, the cross-section parameters of dam-burst are separated from the integral equation and become a coefficient which can be calculated....

A new method is developed for the calcuation of hydraulics characteristics of dam-burst with arbitrary outlet which can be described with a number of broken lines. Combinative-parameters are defined firstly accor-ding to all parameters defining the cross-section of the outlet. A transformation related to the combinative-parameters is deduced thereafter. With this transformation, the cross-section parameters of dam-burst are separated from the integral equation and become a coefficient which can be calculated. The original integral equation of dam-burst, which has been expressed by all shape-parameters, is transformed into a model equation. The model equation can be treated as a pure mathematical problem. Tables and charts can be worked out, which are very convenient to use. The advantage of this method is that the hydraulic characteristics of dam-burst can be obtained straightforward from the cross-section of the outlet.

The lighter danger district of debris flow is Ⅴ_a-District with actual and potential capacity oflight harm or threatening; nearly without danger district of debris flow is Ⅴ_b-District with ncarlyno harm or threatening.Ⅴ_a-District is divided into 15 parts. The area is 27.05×10￣4km￣2 and27% of the area of the upper reaches of Changjiang Revir.Ⅴ_b-District is divided in to 4 parts.The arca is 3.25 × 10￣4km￣2 and 3% of the area of the upper reaches of Changjiang Revir. Thedistrict is distributed over 6 provinces(see...

The lighter danger district of debris flow is Ⅴ_a-District with actual and potential capacity oflight harm or threatening; nearly without danger district of debris flow is Ⅴ_b-District with ncarlyno harm or threatening.Ⅴ_a-District is divided into 15 parts. The area is 27.05×10￣4km￣2 and27% of the area of the upper reaches of Changjiang Revir.Ⅴ_b-District is divided in to 4 parts.The arca is 3.25 × 10￣4km￣2 and 3% of the area of the upper reaches of Changjiang Revir. Thedistrict is distributed over 6 provinces(see Table l).In Ⅴ_a-District ,the activities of debris flowate mainly feeble and feebler,the level of economic development is lower and there are mainlvawaiting development district(area is 17.12 × 10￣4 km￣2). The landform indexes are mainly 4 grade and 5 grade(the relative height h of statistic unitis 1 000-500m and<500m respectively).In the ravine,cutting is shallower and the dynamicconditions of debris flow which is provided by landform is little. Most geologic indexes are 5grade(the product S of fault length and strata weathering coefficient in statistic unit<0.10)and 4 grade(S=0. 15-0.10);The length of main fauIts is 108m /km￣2(in Ⅴ_a-District)and23m /km￣2(in Ⅴ_b-District).Most climatic index is 4 grade, The geologic and landform conditionsand climatic conditions are not favourable to the formation of debris flow.There is none debris flow activity in Ⅴ_b-District. Damages of debris flow are very light andits activity appears only in local area in small scale and low frequency in Ⅴ_a-District,but thehazards of man-made debris flow eaused by reservoir dam burst,may happen. Therefore,man-made debris flow should be prevented emphatically.

Completed in October 1990, Gouhou Reservoir had a storage capacity of 3. 300. 000 cubic meters and its dam was of reinforced concrete faced gravel fill dam with a maximum height of 7lin. Because of long duration of high water level. the phreatic line of the dam was raised, the gravel fill was saturated. and the effective shearing strength was decreased. Under the self-weight of the high wave wall and the relevant soil fill. the subsidence and rotation of the wave wall wereresulted. Then the waterstop was pulled...

Completed in October 1990, Gouhou Reservoir had a storage capacity of 3. 300. 000 cubic meters and its dam was of reinforced concrete faced gravel fill dam with a maximum height of 7lin. Because of long duration of high water level. the phreatic line of the dam was raised, the gravel fill was saturated. and the effective shearing strength was decreased. Under the self-weight of the high wave wall and the relevant soil fill. the subsidence and rotation of the wave wall wereresulted. Then the waterstop was pulled out and the downstream slope near crest lost its stability. The reinforced concrete fsce near crest above the river channel was continuously broken and landsliped, and burst opening was formed' The burst of the dam happened in the evening of August 27, 1993. The lack of elaborately design and construction experience. the loose operation management and the profession management being not carried out in the hydraulic engineering construction are the main lessons to be drawn in this dam burst incident.