金沙江上游白格滑坡黏土化蚀变岩的灾变力学行为研究OA北大核心CSTPCD

The Jinsha River's tectonic junction zone is a typical tectonic melange zone resulting from plate collisions.It boasts a complex geolo-gical structure and hosts unique rock and soil formations with unfavorable engineering properties.Investigating the Baige landslide upstream of the Jinsha River revealed a novel finding:clay-altered rocks,characterized by significant thickness and continuous distribution,were identified on the rear edge of the massive landslide,playing a crucial role in its composition.Through on-site sampling and laboratory experiments encom-passing material composition,disintegration resistance,annular shear,and dynamic triaxial analysis,the catastrophic mechanical behavior of clay-altered rock and its contribution to the formation and evolution of the Baige landslide were elucidated.Key conclusions include:1)The clay-altered rock in the Baige landslide,exhibiting high alteration degrees,results from intense alteration of ophiolite within the Jinsha River's tectonic junction zone.Alteration coefficients range between 0.64 and 0.86,with mineral components predominantly comprising illite,followed by illite/montmorillonite mixed-layer minerals.It demonstrates high susceptibility to disintegration upon contact with water,with a disintegration in-dex surpassing 50%.2)Altered clay exhibits the poorest engineering properties within clay-altered rock formations,with its strength significantly diminished under the influence of water and vibration loads.Increasing water content from 10%to 20%results in a 34%decrease in shear strength.Dynamic strength notably lags behind static strength and diminishes with increasing vibration cycles,playing a pivotal role in facilitat-ing the penetration and failure of slope rock mass structural planes.3)The formation of the Baige landslide's sliding surface is jointly governed by joint structural planes and clay-altered rock,manifesting two predominant modes:thick,soft interlayered clay-altered rock and filling joints and fractures penetrating types.4)The prevalence of numerous massive high-level landslides upstream of the Jinsha River correlates closely with the unfavorable engineering characteristics of clay-altered rocks.The interplay between rock mass structure and distinct lithology constitutes a region-al geological structure prone to slip,warranting attention.This understanding holds significant implications for slope stability analysis and dis-aster prevention along the Dajiang River bank on the eastern margin of the Qinghai-Xizang Plateau.