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Research on the damage and seepage characteristics of unloading rock with high water pressure can help to further understand the mechanism of water inrush in deep mine floor and prevent water inrush. This paper used the RFPA2D-flow finite element software to study the failure and seepage characteristics of unloading rock with high water pressure and high stress and comparatively analyzed the failure modes and seepage characteristics of unloading rock with and without water pressure. The effects of different water pressure differences on the failure of unloading rock and the law of seepage were investigated by analyzing the change of acoustic emission and permeability coefficient with stress. The results showed that the unloading rock without water pressure was brittle failure, and the initial damage of the unloading model with water pressure was earlier than that of the model without water pressure and showed greater brittleness, and its cracks first break through at the bottom of the sample with higher osmotic pressure. With the increase in unloading, the permeability of rock increased gradually until it appeared an abrupt change. The failure mode and permeability law of the rock with different water pressure differences were basically the same, but the greater the pressure difference, the smaller the effective unloading capacity when the permeability coefficient changes suddenly, and the greater the possibility of water inrush in the rock.

As the research base damage and water inrush problem, this article obtains from the body micro units, on the basis of seepage of rock mass and rock mechanics theory, considering the heterogeneity of rock, and established the heterogeneity of rock containing random defects of mesoscopic scale on the seepage flow in heterogeneous model by means of FLAC3D simulation software built-in fish language from the model unit randomly in the unit ID number, total group as defects in the model group, while the rest of the unit as a complete set, the different group gives different mechanics parameter values, implement different defect degrees of homogenization model established The results show that the overall bearing capacity of rocks with high defect degree decreases obviously, and the failure of rocks precedes that of intact rocks.

In order to reduce the construction cost of excessively wet silt roadbeds and improve the compaction quality, this paper studies the compaction characteristics and compaction technology of excessively wet silts through theoretical derivation, indoor experiments, numerical simulation, engineering verification, and other research methods. Based on the pendulum-type liquid bridge structure, this paper uses the Hertz–Mindlin theory, particle motion equation of state, and other theories to modify the force between particles of an unsaturated soil. Through the contact angle, which is a medium, the matrix suction is linked to the water content and is used to approximate the water content state of soil samples. Using PFC3D (particle flow code 3D) numerical simulation software, an unsaturated silt model was established based on Hill contact, and the model parameters were calibrated through basic geotechnical tests and triaxial compression tests. The correctness of the theory is verified by comparing the simulated triaxial compression test of wet silts with the indoor test. By simulating subgrade rolling, considering factors such as the distribution of contact force chain and the variation of compaction degree, the effects of rolling times, strong vibration, and weak vibration on the compaction effect were compared and analyzed. Finally, the optimal rolling and compaction process under the optimal water content is obtained through on-site engineering tests. The results show that: (1) The Hill contact model is reasonable for simulating the wet silt. (2) During the simulation of the roadbed compaction process using PFC3D software, it was found that the compaction degree change during the entire compaction process can be roughly divided into the initial compaction stage and the re-compaction stage. The reasonable number of compaction times was determined to be five through discrete element simulation. (3) It is found from the numerical simulation results that compared to static compaction, both strong and weak vibration compaction can effectively improve the compaction effect of subgrade compaction. The larger the vibration amplitude, the more obvious the improvement of the compaction effect. The compaction effect of strong vibration followed by weak vibration is stronger than that of weak vibration followed by strong vibration. (4) The optimal compaction process obtained under the optimal moisture content of 15% is static pressure once + strong vibration twice + weak vibration twice.