The Experimental Model Analysis On Low-frequency Vibration Characteristics Of The Cutter Head Of The TBM Boring In Nonuniform Hard Rock Stratum

Water resources are unevenly distributed in China,water resources in the south are abundant.In the north,the problem of agricultural water use has been attracting much attention.Agricultural water is huge and important,a variety of measures have been taken to address this problem,of which irrigation is a very common means.However,there is no corresponding standard in the long-term use of sewage water to ensure that the water quality is difficult to ensure that the toxic and hazardous substances in the sewage exceeded a series of environmental pollution problems,heavy metal characteristics of heavy metals into the soil will not be decomposed and can go through the gas Into the groundwater,serious harm to human health.The paper relies on the National Natural Science Foundation : Study on Interfacial Migration Mechanism and Time Scale Benefit of Chrome Empty Belt-Aquifer(Item No.41402225)?The interaction and migration characteristics of Cr(?)with soils were analyzed by static adsorption test,soil column leaching experiment and sand tank simulation experiment.The results were used to establish the Hydrus model to predict various pollution Cr(?),which provides the basis for the treatment of heavy metal pollution.In this paper,based on a large number of indoor experiments on the basis of the following con Clusions:1?Static adsorption testThe effects of pH on the adsorption of Cr(?)and the adsorption of Cr(?)on soils with different depth were observed.The results showed that the p H value of the soil at different depths of the sampling point was affected by adsorption experiment,adsorption kinetic experiment and adsorption thermodynamics experiment.The results are different,and the adsorption capacity of deep soil is generally higher than that of surface soil.The adsorption of Cr(?)on the soil can be divided into two stages: rapid and slow.The rapid adsorption of Cr(?)occurs at the initial stage of adsorption.The adsorption rate of the soil decreased after a certain period of time,until the adsorption equilibrium was reached.This stage was the slow stage.The fast adsorption stage of different depth soils had different duration,and the duration was related to the soil type.2?Soil column leaching experimentThe vertical migration of Cr(?)in the unsaturated zone is simulated by using the soil column model.The experimental results show that the soil porosity is uniform,the soil properties are constant,the seepage velocity is stable and the Cr(?),Cr(?)can be detected after a certain period of time,and the concentration of Cr(?)at the bottom of the instantaneous source is increased first and then decreased,and the highest The concentration is lower than the initial concentration of Cr(?)added to the top of the soil column,and the final concentration is zero.The concentration of Cr(?)in the bottom of the continuous source soil column is the same as the concentration of Cr(?)at the top of the column after a period of time.These characteristics affect the adsorption of Cr(?)with the blocking effect: delay Cr(?)at the bottom of the emergence time,must be reduced Cr(?)concentration.But the effect of interception with the increase in pollution gradually weakened,beyond the threshold after this effect is no longer obvious.3,Hydrus modelThe Hydrus-1D model was established by using experimental data.The migration process of Cr(?)in the vertical direction was analyzed,and the migration characteristics of Cr(?)were predicted.