Study On Damage Mechanism Of Plant-growing Consolidation Material/Pisha Sandstone Under Drying-wetting Cycles

The plant-growing consolidation material(hydrophilic polyurethane)developed for the treatment of water and soil loss in the Pisha sandstone area,referred to as W-OH,has a good anti-corrosion effect.After the W-OH and water are mixed,the composite solution can form a consolidation layer on the surface of the Pisha sandstone,which is well wrapped and adhered to the surface weathered Pisha sandstone.The good performance of the consolidation layer is the basic premise of W-OH to control soil erosion in the pisha sandstone area.In the external environment,especially the dry-wet cycles,so that the consolidation layer destruction.In order to ensure the long-term effectiveness of the consolidation layer,it is necessary to study the failure mechanism of the consolidation layer under the dry-wet cycles.In this paper,the consolidation time of W-OH solution and the water absorption and dehydration properties of W-OH consolidated bodies were studied.The fracture characteristics of W-OH consolidated bodies under dry and wet cycles were studied.The adhesion process of the Pisha sandstone and the water loss spalling process were analyzed.The adhesion model and water damage model were established to obtain the water stability constant.Finally,the model was verified by the unconfined compressive strength test of the W-OH Pisha sandstone complex.The main work of this paper is:1.Based on the Brookfield DV3T viscometer and constant temperature water bath,the consolidation time of different concentrations of W-OH reacted with water at different temperatures was determined.It was found that the consolidation time decreased with increasing temperature and W-OH concentration.In this way,the relationship between the consolidation time of W-OH and water and the temperature and W-OH concentration is established.The water absorption and dehydration properties of W-OH consolidated bodies with different concentrations were studied.It was found that with the increase of W-OH concentration,the water absorption rate K_?,ultimate water absorption ratew_?and dehydration rate K_d of W-OH consolidated bodies increased.And the dehydration rate K_d of the W-OH consolidated bodies is smaller than the absorption rate K_?,that means the W-OH consolidated bodies has better water retention.2.Based on the mechanical properties analysis of different concentrations of W-OH consolidated bodies in the dry-wet cycles of the instron universal testing machine,it was found that the elastic modulus E of the same concentration of W-OH consolidated body fluctuated less during the dry-wet cycle,it means that different concentrations of W-OH consolidated bodies have excellent resistance to dry and wet cycles;At the same time,the surface morphology of the solids with different concentrations under dry and wet cycles was analyzed by metallographic microscope.It was found that the surface of the W-OH solidified body became rough,and the concentration of W-OH solidified surface changed.The slower the roughness,the rougher the surface topography accelerates the shedding between W-OH and the sandstone.3.Based on the adhesion process and water damage process of W-OH Pisha sandstone,the W-OH and Pisha sandstone adhesion model and water damage model was established,and the water stability constant is obtained by the energy change ratio of the water damage process to the adhesion process.It is found that the greater the W-OH concentration,the greater the water stability constant,that means the stronger the W-OH Pisha sandstone complex is resistant to dry-wet cycles,the more difficult the W-OH is to break away from the Pisha sandstone.Based on the unconfined compressive strength test of W-OH Pisha sandstone complex,the unconfined strength ratio T of W-OH Pisha sandstone complex before and after the dry-wet cycles was obtained.It was found that the W-OH concentration was larger,the unconfined strength ratio T bigger.The relationship between the unconfined strength ratio T and the water stability constantgof W-OH Pisha sandstone before and after the dry-wet cycles was established,and the correlation was good.The W-OH and Pisha sandstone adhesion model and water damage model were verified.