Presents a systematic and comprehensive study of hydraulicfracturing, original in its concentration of core soilproblems
There have been a number of well-studied cases in which damshave failed or been damaged by concentrated leaks for no apparentcause. In some of these experiences, investigators concluded thatdifferential settlement cracks were the probable causes, eventhough no cracks were seen on the surface. In these examples, itwas not determined whether the crack was open before the reservoirfilled or whether it might have opened afterward. In severalunsolved problems on the safety of the earth-rock fill dam, theproblem of hydraulic fracture in the soil core of the earth-rockfill dam is one that is widely paid attention by designers andresearchers. Hydraulic fracturing is generally considered as a keycause which may induce the leakage of the dam during firstfilling. In this extensive book, a new numerical simulate method issuggested. The method is based on the conventional two-dimensionalfinite element technique, and the theoretical formulations tocalculate energy release rate using virtual crack extension method.The influence factors on convergence of calculated J integral areinvestigated. The accuracy of the calculated J integral is verifiedby analysing the three typical problems in Fracture Mechanics, inwhich propagation of crack may follow mode I, mode II and mixedmode I-II respectively. Using the new numerical method, the factorsaffecting the occurrence of hydraulic fracturing in the earth-rockfill dam are investigated. The investigating results indicate thatincreasing any of the Young s modulus, the Poisson sratio and the density of the core soil is helpful to reduce thelikelihood of the occurrence of hydraulic fracturing. Thelikelihood of the occurrence of hydraulic fracturing increases withincreasing the water level or the crack depth. The lower part ofthe dam core is the zone in which the phenomenon of hydraulicfracturing may be induced easily. As an example to analyse theability of earth-rock fill dam to resist hydraulic fracturing, theNuozhadu Dam located in Western China is analysed.
* Presents a systematic and comprehensive study of hydraulicfracturing, original in its concentration of core soilproblems * Focuses on the problem of hydraulic fracturing in earth-rockfill dams from three aspects; conditions and mechanisms ofhydraulic fracturing, criterion of hydraulic fracturing, andnumerical method on hydraulic fracturing * Examines advanced laboratory soil testing, application ofnumerical methods and field testing/monitoring, all needed for abetter understanding of hydraulic fracturing in earth/rock filldams * Provides an essential reference in an area of scarce researchin this field, and the need in high earth dam construction indeveloping countries is pressing
Ideal for researchers in Hydraulic and Geotechnical EngineeringFields; Students on Masters or PhD courses; as well as Designersand Constructors in Hydraulic and Geotechnical EngineeringFields.