Calculation Of Surrounding Rock Humidity Field Of Roadway Based On One-dimensional Moisture Movement Law Of Expansive Rock

During underground construction and mining,rock drilling,mining and other construction water cannot be discharged in time and smoothly,which often leads to accumulation of water inside the roadway and formation of a high-humidity environment.When the roadway and ketone chamber are excavated in the expansive rock mass,the moisture condition changes with the surrounding rock,which causes the humidity condition of the surrounding rock to change.The volume expansion of the surrounding rock creates a huge expansion pressure on the support and lining,and the surrounding rock softens.It causes the strength of surrounding rock to decrease,which brings serious difficulties to the stability control of surrounding rock of expansive rock.Due to the complex geology of expansive rock,sampling of rock samples and on-site monitoring are difficult.The problem of surrounding rock humidity field has become a prominent problem in roadway engineering.According to the similarity theory,the paper uses the indoor test to prepare similar materials of expansive rock to simulate the expansive rock.The water migration test was carried out using a proportioning material to study the dynamic migration of water inside the expansive rock.Based on the experimental study of the one-dimensional water migration law of expansive rock,the interpolation calculation model of surrounding rock of expansive rock roadway is established,and the model test is used for analysis and comparison.The purpose is to provide calculation for the problem of humidity field encountered in excavation and use of expansive rock roadway.reference.The results achieved are as follows:(1)Quartz sand,gypsum,kaolin,bentonite,rosin alcohol solution and water were selected as raw materials,and the orthogonal test of similar materials ratio of 5 factors and 4 levels was designed.Similar materials with different ratios have a wide range of expansibility and moisture absorption capacity,which can meet the requirements of similar rock mass model tests for rock mass similar materials,and also provide basis for the selection and proportion design of other rock mass test materials.(2)The water content inside the similar materials of expansive rock increases with time,and the growth rate of water content decreases with time and eventually stabilizes.After the water migration is stable,the water content is considered to be layered in the sample,and the water content change gradient in the near-absorbent surface of the sample is larger.As the moisture absorption depth increases,the water content decreases linearly until the water migration depth Not changing.(3)The moisture absorption environment,material swelling and water migration direction have an effect on the water migration depth and water content distribution of similar materials of expansive rock.The migration depth is the smallest when the water migrates upward,and the migration depth is the largest when the migration is downward.The difference in migration depth between similar materials in weakly expansive rock materials in different moisture absorption environments can reach 14.3%~25%,and the migration depth of similar materials in strong expansive rocks is 19.2%~25%.The water content and water migration depth inside the similar materials of strong expansive rock are larger than those of weak expansive rock.When the moisture absorption environment changes,the water content distribution and water migration depth inside the similar materials of the expansive rock change with the temperature,and the water content of the near-absorbent surface area of the sample increases more than the area far away from the moisture absorption surface.(4)Based on the water migration test data,according to the similarity theory,a threedimensional interpolation calculation model consisting of two-dimensional tunnel surrounding rock humidity field and water migration time is established by using the cubic spline function,and the main implementation steps of the calculation are clarified.Provide a calculation reference for the dynamic process of the surrounding rock humidity field of a given humidity variation range.(5)The moisture field of the surrounding rock of the expansive rock roadway is distributed outwards in a layered manner,and the water content increase in the boundary area of the surrounding rock near the roadway is larger than that away from the boundary area of the roadway.The water inside the surrounding rock shows three-stage migration characteristics with time.The initial stage is the violent migration stage,the medium stage is the migration mitigation stage,and the later stage is the migration stability stage.After the surrounding rock of the roadway is exposed to the moisture absorbing environment,the water diffusion depth in the short term can reach the total.The depth is 26.3%~34.3%,then the water migration rate is gradually reduced,and finally reaches the limit.Rock mass expansion and gravity are the main factors for the variation of surrounding rock humidity.The humidity variation range of the strong expansive surrounding rock and the water content at the same location are larger than the weak expansive surrounding rock.The variation range of the surrounding rock humidity above the roadway is affected by the water migration.Next,the side of the surrounding rock has the largest range of humidity changes.In addition,the internal temperature of the roadway also has a certain influence on the humidity distribution around the surrounding rock.When the temperature increases,the migration rate of water in the surrounding rock increases,and the moisture content of the surrounding rock around the roadway increases.