Papers by Author: Shu Cai Li

Abstract: Numerical simulations play a significant role in explosion in a mass of soil due to an underground explosive. Common methods available in hydrocode for fluid-solid coupling process are contact algorithm, Lagrange algorithm, and Arbitrary Lagrange-Euler (ALE) algorithm. A numerical simulation of explosion process with concentrated charge in a mass of soil was carried out by using three methods in this paper. The dynamic response of soil medium, the formation and development law of explosion cavity and the explosion wave propagation law in soil were simulated. Merits and drawbacks of three different methods are analyzed in the aspect of modeling, simulation results and computing cost.

Abstract: Qingdao Metro Line 3 is the first subway line in Shandong province, some tunnels need to cross water-rich sandy layers. At the time of passing through the water-rich sandy layers, how to maximum the deformation characteristics of the tunnel during excavation becomes the critical problem of the design and construction. This paper studies Qingdao Metro Line 3, directs at water-rich sand layer section YK16+382, with the use of on-site monitoring and measuring instruments, analyses the characteristics of ground deformation of the cross section. And we calculated the deformation by Flac3D numerical simulation in YK16+382 cross section, studied the arch and surface subsidence and convergence deformadon variation of convergence. Finally compare site monitoring measurement with numerical computational results and then we can get the convergence of arch and surface subsidence and convergence deformadon, provide theoretical guidance for the actual construction.

Abstract: Water-rich and soft fault fracture zone is the geologic disaster source of water and mud outbursts in tunnel while the curtain grouting is an effective management method. To determine appropriate parameters of the grouting reinforced circle, depending on fluid-solid coupling theory and numerical simulation of the seepage fieldstress field, the influence of parameters to the water inflow and stability is analyzed while grouting effect was evaluated from the two aspects of reinforcement and water plugging. The conclusion show: the permeabilitystrength and thickness of the grouting reinforced circle are important factors of water inflow and surrounding stability while the choice of the thickness is inflected by the permeability and strength, when which reached a certain value the minimum thickness of the grouting reinforced circle is gotten.

Abstract: Damaged mountain of Ji'nan springs city impact the landscape of the city and the surrounding and traffic along seriously, and affected the city's image and the construction of the beautiful spring city and ecological civilization seriously. They produced a new geologic disaster danger, and threaten the safety of the local people's life and property. Landscape Effect Degree (LED), as a comprehensive index, can be used to quantitatively evaluate the landscape effect degree of the damaged mountain for the city and traffic along. Study on quantitative evaluation and analysis of the impact of mountain landscape damage in Ji'nan City. Comparison and validation of the actual and damaged mountain governance work can verify the display of influence, and quantitative index for damage control plan, and ordered rectification, and the mine recovery, and treatment effect what was analyzed, and the improvement of the ecological environment analysis, and vegetation growth situation analysis vegetation ecological suitability assessment. It can provide scientific basis. Through calculation and analysis, 148 damaged mountain Ji'nan city the three districts and one line visual range, landscape effect degree very serious was 111, accounted for 75%, and severe in 31, accounting for 21%, and the general point of 3, 2%, and lighter point 3 that accounted for 2%. The evaluation results accord with the actual situation of Ji'nan, and it shows that the method for landscape evaluation is applicable.

Abstract: The transient electromagnetic method (TEM) has sensitive characteristics of low resistivity of water containing. The equivalent plane method based on whole space theory is used in coal mine goaf water TEM detecting. The mine goaf water was forward simulation. The geoelectric model of mine goaf water was equivalented to low resistivity layer thickness. The geoelectric model was forward calculated, and it was differential imaged. Then it found the apparent longitudinal conductance differential imaging reflect the most sensitive. The field experiment was conducted in two mine goaf water in Xiezhuang coal mine. The central loop device was selected as working device. The launch wire frame is length of 2m and 8 turns. A receiving device is receiving probe and the effective area is 212m². The Water distribution range of goaf water in-300 of the seven mining area in front of retaining wall is large, and the water body is deep.

Abstract: In this paper, the mechanical behavior of excavation and support construction of Weishe tunnel, which is a section of the Yangwu expressway, is studied quantitatively using 3D finite difference numerical simulation method. A sequential excavation method is used and the results show that the vault settlement occurs mainly on the phase of upper bench excavation. The convergences of upper and lower sidewalls occur mainly on the phase of lower bench excavation. During the construction, the surrounding rock pressure in the vault and sidewall of the tunnel decrease. Axial force of anchor reaches the maximum value after the finish of second lining. However, the surrounding rock pressure and internal force of steel arch reach the maximum value after completing the upper bench excavation, and then become as smaller as half of the peak value during the lower bench excavation.

Abstract: Based on the basic principle of the efficacy coefficient method, a model of rockburst intensity prediction was established. Considering the key affecting factors of rockburst, three factors were selected as evaluation indexes including the ratio of maximum tangential stress and rock uniaxial compressive strength, the ratio of compressive and tensile strength of rock and elastic energy index. Finally, the model was applied to the rockburst prediction of water diversion tunnel of Jiangbian hydropower station and the results show that the method is reliable, and it provids a new idea to predict rockburst.

Abstract: In order to study the safety mining of the deep buried coal seams being threatened by high pressure karst water, relative impermeability of the Ordovician top is demonstrated through studying lithology，filling degree of the karst fissures as well as wash water quantity, in the Baode mine field. Furthermore, the main influencing factors on impermeability of coal seam floor are analyzed, and divisional risk assessment of floor water-inrush from the Ordovician karst aquifer is performed. Overall，by considering the relative impermeable strata in the Ordovician top, the accuracy of risk assessment on coal floor water-inrush can be improved.

Abstract: Water-bearing fault of subsea tunnel has fissure water developed, fractured surrounding rock with low strength, which gets a risk of sudden water inflow and affects the tunnel security. This paper takes the geological forecast and treatment for water-bearing fault of the Qingdao kiaochow bay subsea tunnel for example, according to the water assignment characteristics, using the detect method of TEM and advance borehole to make accurate decision for the position of water-bearing body、the scale of fracture zone and the inflow of water. Through the analysis of results, the grouting form, materials and parameters are chosen and adjusted. The grouting material seals the water flowing fracture, forming water-stopping curtain outside tunnel excavation contour line and strengthening the fault fracture zone to improve the stability of rock.

Abstract: Reinforcement corrosion is one of the main causes for the deterioration of reinforcement concrete structure. And it seriously affected mechanical properties of anchor structure system of underground engineering under complicated erosion environment. Based on elastic theory and assumption of maximum tensile-stress failure criterion, together with construction process of anchor structure and rust expansion critical process, reinforcement rust expansion mechanical model of anchor structure system was simplified. Elastic criterion of different initial cracking mode was rewarded under different stress ratios. According to analysis of critical cracking mode of different medium, cracking order of mortar and surrounding rock depended on their material parameters, in-situ stress and thickness of mortar cover. Critical cracking conditions of different medium without effect of in-situ stress was rewarded. The result provides a useful reference for analysis of mechanical deterioration mechanism of anchor structure and design of support structure of underground engineering.