scholarly journals Analysis of Collapse Mechanism and Treatment Evaluation of a Deeply Buried Hard Rock Tunnel

2020 ◽  
Vol 10 (12) ◽  
pp. 4294 ◽  
Author(s):  
Shifan Qiao ◽  
Ziyong Cai ◽  
Junkun Tan ◽  
Ping Xu ◽  
Yonggang Zhang
Keyword(s):  
Treatment Method ◽  
Field Investigation ◽  
Engineering Problem ◽  
Surrounding Rock ◽  
Tensile Fracture ◽  
Comprehensive Treatment ◽  
Collapse Mechanism ◽  
Tunnel Face ◽  
Treatment Measures ◽  
Rock Tunnel

Collapse is one of the most dangerous geological disasters in tunnel construction, and it is an urgent engineering problem which needs to be solved. Taking the collapse of the top of an actual tunnel face as an example, through field investigation and theoretical calculation methods, the mechanism of tunnel collapse was studied, and the treatment and evaluation of the collapse area were proposed based on field monitoring data. The results show that the extrusion and bulging deformation on the palm surface and the tensile fracture in the top inclined stratum led to the shear slip of the block along the structural surface and the local collapse of the surrounding rock. Based on the block theory, the potential unstable block at the top of the tunnel was successfully identified, and the treatment method of ‘protecting before filling and then digging’ was proposed. The comprehensive treatment measures of advance bolts, steel arch support, collapse backfill, and step excavation were adopted, with on-site monitoring followed up step by step. Based on the analysis of surrounding rock deformation and stress characteristics, in this paper we demonstrate that the treatment effects of the collapse area are good, and ensure the safety and smooth progress of construction. The proposed treatment method achieved the expected goal and was shown to be able to provide successful treatment for similar collapse cases of tunnel engineering.

scholarly journals Analysis of the Causes of the Collapse of a Deep-Buried Large Cross-Section of Loess Tunnel and Evaluation of Treatment Measures

2021 ◽  
Vol 12 (1) ◽  
pp. 161
Author(s):  
Dengke Wang ◽  
Jianjun Luo ◽  
Kaiming Shen ◽  
Liping Gao ◽  
Feilong Li ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Reduction Rate ◽  
Atmospheric Precipitation ◽  
Horizontal Stress ◽  
Surrounding Rock ◽  
Comprehensive Treatment ◽  
Original Design ◽  
Site Monitoring ◽  
Treatment Measures ◽  
Initial Support

To address the problem of the collapse of the roof of the Bailuyuan tunnel during construction, the causes of collapse were analyzed, targeted treatment measures were proposed, and the effects of the treatment measures were evaluated through on-site monitoring and three-dimensional numerical simulations. The results showed that the particular characteristics of loess and the synergy of groundwater were the internal causes of the tunnel’s collapse as well as, to a certain extent, atmospheric precipitation. Therefore, the combination of multiple factors contributed to the tunnel’s collapse. Untimely monitoring and measurement, as well as the low initial support parameters, reflect a lack of human understanding of the collapse. Based on the analysis of the causes of the collapse, comprehensive treatment measures for inside and outside the tunnel are proposed, which are shown to be effective and to be capable of preventing the occurrence of further collapses. After the collapse treatment, the measured maximum settlement of the tunnel vault was 65.1 mm, the maximum horizontal convergence was 25 mm, the maximum surrounding rock pressure was 0.56 MPa, and the maximum stress on the steel arch frame was 54.34 MPa. Compared with the original design plan, the vertical stress, horizontal stress, and shear stress of the surrounding rock obtained from numerical simulation after the collapse treatment were greatly reduced, the reduction rate at the vault reached 50%, and the safety factors of the initial support positions after treatment met the specification requirements. The research results can provide engineering guidance for the design and construction of large-section tunnels crossing deep-loess strata, and they are of important engineering significance.

scholarly journals Study on treatment method of low efficiency well in S12 block

2021 ◽  
Vol 261 ◽  
pp. 03061
Author(s):  
Changyan Zhang
Keyword(s):  
Treatment Method ◽  
Technical Support ◽  
Oil Wells ◽  
Optimal Treatment ◽  
Comprehensive Treatment ◽  
Distribution Law ◽  
Reservoir Heterogeneity ◽  
Integrated Research ◽  
Treatment Measures ◽  
Low Efficiency

In recent years, the production decline of some oilfields is obvious, and a large number of oil wells begin to be in inefficient or ineffective production. Only by controlling these wells can the oilfields maintain effective production. By means of dynamic and static multidisciplinary integrated research, through elaborate dissection of typical potential blocks, the optimal treatment measures are selected from four aspects of “ reservoir heterogeneity and production status, type and distribution law of remaining oil, causes of low efficiency wells, classification and comprehensive treatment countermeasures and methods”, so as to provide technical support for potential tapping and comprehensive treatment of old oilfields.

scholarly journals Obvious Reduction of the Tumor Size in Dedifferentiated Liposarcoma in a Lung Metastasis Patient Receiving Individualized Treatment

2021 ◽  
pp. 1080-1084
Author(s):  
Xin-Li Wang ◽  
Jia-Yao Gong ◽  
Yan Xue
Keyword(s):  
Quality Of Life ◽  
Therapeutic Effect ◽  
Tumor Size ◽  
Systemic Treatment ◽  
Treatment Method ◽  
Palliative Surgery ◽  
Dedifferentiated Liposarcoma ◽  
Comprehensive Treatment ◽  
Back Surgery

Abdominal metastasis is relatively rare in dedifferentiated liposarcoma of the shoulder and back. Surgery is the best treatment option, whether it is radical or palliative surgery. Chemotherapy is the standard systemic treatment for advanced unresectable/metastatic patients, but the therapeutic effect is limited. Here, we treat advanced abdominal dedifferentiated liposarcoma through a comprehensive treatment method of targeting, surgery, and chemotherapy, which improves the quality of life of the patient, and shrinks the tumor significantly.

Study on the Truss Support Technology for Coal Side in a Soft Broken Coal Roadway Under High Stress

2012 ◽  
Vol 524-527 ◽  
pp. 360-363
Author(s):  
Shou Yi Dong ◽  
Qi Tao Duan ◽  
Fu Lian He ◽  
Qi Li ◽  
Hong Jun Jiang
Keyword(s):  
Production Condition ◽  
High Stress ◽  
Field Investigation ◽  
Surrounding Rock ◽  
Theory Analysis ◽  
Large Section ◽  
Cable Channel ◽  
Coal Roadway ◽  
Measurement Results ◽  
Steel Truss

The coal side deformation and sliding can not be effectively controlled by use of the traditional bolt or cable support in the high stress crushed surrounding rock and large section roadway. For solving this problem, the new prestressed truss support technology is put forward, and its supporting principles of roof and two walls are stated. The mechanical model of cable-channel steel truss is established, and then the tensile strength of the cable and the maximum deflection of the channel steel are derived. By way of field investigation, mechanics theory analysis and actual production condition, the scheme is defined and applied in the replacement roadway. Measurement results of surrounding rock behavior show that the coal side displacement is no more than 254mm and the roof convergence is less than 172mm. Apparent economic and technical profits have been achieved.

Judgement Method for Surrounding Rock Stability of Guanjiao Tunnel Based on Catastrophe Theory

2011 ◽  
Vol 90-93 ◽  
pp. 2307-2312 ◽  
Author(s):  
Wen Jiang Li ◽  
Su Min Zhang ◽  
Xian Min Han
Keyword(s):  
Plastic Strain ◽  
Catastrophe Theory ◽  
Soft Rock ◽  
Surrounding Rock ◽  
In Situ Monitoring ◽  
Engineering Practice ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Rock Tunnel

The stability judgement of surrounding rock is one of the key jobs in tunnel engineering. Taking the Erlongdong fault bundle section of Guanjiao Tunnel as the background, the stability of surrounding rock during construction of soft rock tunnel was discussed preliminarily. Based on plastic strain catastrophe theory, and combining numerical results and in-situ data, the limit displacements for stability of surrounding rock were analyzed and obtained corresponding to the in-situ monitoring technology. It shows that the limit displacements obtained corresponds to engineering practice primarily. The plastic strain catastrophe theory under unloading condition provides new thought for ground stability of deep soft rock tunnel and can be good guidance and valuable reference to construction decision making and deformation managing of similar tunnels.

scholarly journals Analysis on Loose Circle of Surrounding Rock of Large Deformation Soft-Rock Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Rui Wang ◽  
Yiyuan Liu ◽  
Xianghui Deng ◽  
Yu Zhang ◽  
Xiaodong Huang ◽  
...  
Keyword(s):  
Large Deformation ◽  
Theoretical Calculations ◽  
Rapid Development ◽  
Field Tests ◽  
Soft Rock ◽  
Strength Criterion ◽  
Surrounding Rock ◽  
Distribution Law ◽  
Geological Conditions ◽  
Rock Tunnel

With the rapid development of tunnel construction in China, deep buried and long tunnel projects are emerging in areas with complex engineering geological conditions and harsh environment, and thus large deformation of tunnels under conditions of high in situ stress and soft rock becomes increasingly prominent and endangers engineering safety. Therefore, it is of great significance to control the deformation and improve the stability of surrounding rock by analyzing the thickness and distribution law of loose circle according to the unique mechanical properties and failure mechanism of surrounding rock of large deformation soft-rock tunnel. Based on unified strength theory, this paper deduces the radius calculation formula of the loose circle by considering the influence of intermediate principal stress. Furthermore, the theoretical calculations and field tests of the loose circle in the typical sections of grade II and III deformation of Yuntunbao tunnel are carried out, and the thickness and distribution law of loose circle of surrounding rock of large deformation soft-rock tunnel is revealed. The results show that the formula based on the unified strength criterion is applicable for a large deformation tunnel in soft rock.

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