Experiment Study On The Cracking Mechanism About Loess Ground Under The Environment Of The Cave

Loess is widely distributed in China, the loess has loose, large pores, collapsible features,in the Loess Plateau area are landslide, collapse, debris flow, collapse of a series of geologicalhazards. These geological disaster breeds and occurrence and loess body joints, fracture hasthe very big relations, and the development in the very great degree and the externalenvironment changes of temperature and humidity, rainfall, irrigation induced soil dryingwetting cycle there is an inevitable link joint fissure formation of Loess body. In this thesis,the National Natural Science Fund Project "Cave Erosion Environment of loess slope slidemechanism research" as the basis, the shrinkage and crack mechanism of loess in the innerchamber temperature and humidity in drying process of reconstruction field study in the initialsaturation.Through field investigation and indoor reconstruction of temperature and humidity fieldexperimental research, experimental study on the shrinkage properties of loess sample verifythe drying shrinkage of loess can be divided into stages: normal contraction stage, residualshrinkage stage, zero contraction phase. The experimental results of MCG-B model andGRO C model validation sample, the higher fitting degree is greater than0.997, obtained byliquid paraffin replacement method in Loess contraction curve measured with high accuracyand reliability. And then in the indoor environment temperature and humidity changereconstruction on Loess simulation of temperature and humidity shrinkage crackingmechanism, summarizes the Loess cracking and temperature, humidity, moisture content,thickness and lateral dimensions, shape of specimen, binding and other factors, and expoundsthe crack process of loess samples in dry cracking derived propagation. Expression of volumechanges of the dry shrinkage cracking process of loess sample drying s hrinkage free andboundary constraints in the summary. Proposed, verified the hypothesis: loess samples freedrying shrinkage variable volume shrinkage process is equal to the outer boundary binding ofloess under the crack volume and systolic volume and.The test results with the field investigation, the moisture migration in Loess channelconsists of loess body joints, cracks, caves and so on, these channels makes the surface waterquickly reach the formation following promoting or inducing the landslide, collapse, landslideand other geological disasters, so the research on loess landslide, collapse, cracking on thelandslide and other geological disasters control, prevention, management has certaintheoretical guidance and practical significance.