Study On The Characteristics Of Collapse Block Diameter Of Near-Horizontal Red Bed Rock Mass In Sichuan Area

Sichuan’s red bed region is mostly formed by the interplay of soft and hard rocks such as sand and mudstone.Collapse catastrophes occur frequently in this area due to differential weathering,posing a significant threat to the safety of people’s lives and property.To avoid and mitigate the damage caused by collapse,a basic knowledge of the scale and destructiveness of collapse is required.The collapse destructiveness is best interpreted by the collapsed block diameter.At the moment,the destructiveness of collapse is mostly determined by the cycle,time,and magnitude of previous failures,and there is no foundation for predicting the severity of collapse catastrophes that occur for the first time or have no noticeable forewarning.As a result,it is critical for collapse prevention and control to further estimate the collapse degree or destructiveness by researching the collapse block diameter.Through extensive data collecting and field examination of near-horizontal red layers in Langzhong City,Longquan Mountain Area,Qianwei County,and Yibin City,this paper analyzes and explores the link between joint spacing and layer thickness.The relationship between joint spacing and layer thickness is validated in this research through numerical simulation calculations and structural physical simulation experiments,and its affecting elements are investigated simultaneously.The layer thickness is then used to judge the size of the joint spacing,and the maximum block diameter that may be generated during the collapse is predicted further,in order to predict the scale and destructive size that may occur when the collapse occurs and to carry out more targeted protection.Through field investigation and data collection,this paper obtains data on joint spacing,layer thickness,lithology,and interaction type of red bedrock mass in the Sichuan area,and then summarizes and analyzes the data to determine the relationship between layer thickness and joint spacing,as well as the influence of other factors.Numerical simulation software is used to simulate the compression of sand-shale interbedded rock mass under various conditions in order to investigate the effect of layer thickness,applied displacement,and elastic modulus on joint spacing and the layer thickness/joint spacing ratio.Because the rock mass will most likely create a fold as a result of restrictions and self-resistance when squeezed,this fold may be thought of as a sinusoidal curve.As the crests and troughs of the rock formation are the most prone to joints,the distance between the two can be estimated as the joint spacing.Utilizing tectonic physical modeling experiments,this paper simulates the process of forming folds under compression of rock mass,conducts experiments with varying layer thicknesses,extrusion distances,and elastic modulus,and records and analyzes the experimental results.The experimental and numerical simulation findings are then compared and validated with the field research conclusions,yielding a more accurate technique or rule for estimating joint spacing.It is discovered that layer thickness and joint spacing have a linear relationship.Based on this,we could forecast the maximum block diameter of a collapse,allowing us to assess the degree of the collapse.This allows for more targeted preventative efforts and more precise design requirements to be implemented before the collapse happens.