科创中国

Traditional electric strain sensors have poor waterproof performance and low precision, so they are unsuitable for laneway water inrush model test. To solve these problems, a novel fiber-optic grating strain sensor based on similar material to model is developed. The fiber-optic sensing network is established using the wavelength division multiplexing(WDM) technology and F-P demodulating technology, and the software with real-time display and automatic warning is compiled. The system is used in laneway water inrush model test and 14 fiber-optic Bragg grating strain sensors are pre-embedded around the laneway to monitor the strain of surrounding rock in the processes of laneway pushing, model loading and laneway expanding excavation. The results indicate that the presented system has higher precision and is waterproof. Moreover, it can successfully capture the precursory information 4206 s before water inrush. Therefore, it provides a novel and effective approach for forecasting water inrush of mine.

静 王;Zheng Fang Wang;Qing Mei Sui;术才 李;Shu Chen Li;Li Ping Li;滨 刘

Guangdianzi Jiguang/Journal of Optoelectronics Laser

2010-12

The geotechnical performance of a pilot unlined crude oil storage caverns in granite is assessed using finite element method. Laboratory and field tests were performed to determine the geotechnical properties of the granite. Numerical simulations were carried out to assess the groundwater dropdown and stability of the caverns according to the test results. 5 numerical cases with different permeability coefficients were performed to investigate the influence of permeability coefficient. The simulation results indicated that the operation period of the storage caverns will be less than the designed period if there is no groundwater supply system. It was also found that there is an approximately linear relation between groundwater inflow flux and permeability in the double logarithm space. On the stability of the caverns, it is shown that the stability of pillars between different caverns is different as a result of the different stress paths experienced of the pillars.

Z. Wang;术才 李;L. Qiao

2013

To solve the support problems of high stress roadways in deep mines, we developed a new 3D U-type confined concrete support system from the conventional U-type steel arch centering. Its core is the U-type confined concrete (UCC) arch centering. With a real scale mechanical test system for the confined concrete arch centering in underground engineering and numerical calculation methods, we studied in depth on the mechanical properties and deformation & failure mechanism of UCC arch centering (UCCAC). The results of the study show the yielding load and the limit load of UCC29 arch centering is 1230. kN and 1310. kN respectively in even pressure loading conditions; and a slight difference between the laboratory test and the numerical simulation on these two is 8.86% and 12.5% respectively. The deformation form of the arch centering is "vault uplifting, legs introverting and the overall shape becomes oval" and the largest deformation occurs between the middle of the legs and the arch centering springing. The deformation and failure mechanism of arch centering is the partial strength failure causes the entire arch centering to lose its stability. The application on site shows the UCCAC has a superb effect on the surrounding rock control; therefore, the UCCAC is a new effective support for the high stress roadways in deep mines.

Q. Wang;B. Jiang;术才 李;D. C. Wang;F. Q. Wang;W. T. Li;Y. X. Ren;N. B. Guo;X. Shao

Tunnelling and Underground Space Technology

2016-1-1

It is one of the important research projects in the field of controlling water-inrush from roof that the calculating method of water flowing fracture height caused by coal mining. The traditional theoretical method to calculate water flowing fracture is the experiential formula, which is obtained during mining shallow coal layer and only mining thickness factor is considered in the experiential formula. Apparently, it is one-sided to calculate water flowing fracture height with the experiential formula. Based on the rock pressure control theory, combined with similar material simulation test, the theoretical formula to calculate water flowing fracture height was deduced, in which the mining depth, length of working face, mining thickness and roof composition facture were included. The application value of the formula is proved with the example of the 1409 working face in Huafeng colliery.

Tong Bin Liu;Long Qing Shi;Jin Han;Jiu Chuan Wei;Lu Zhu;术才 李

Meitan Xuebao/Journal of the China Coal Society

2006-12

In the Jennings criterion, which is commonly used to estimate the shear strength of nonconsecutive jointed rock masses, the estimated values deviate from the actual values due to the criterion failure to consider the joint undulating angle and the weakening of the mechanical properties of the rock bridge during shearing. Based on the modified Jennings criterion, this paper considers the influence of normal stress and joint continuity on the degree of weakening of the rock bridge's mechanical parameters and presents a new correction method to further modify the Jennings criterion. The collection of undisturbed rock samples from the study area and the creation of joint(s) for laboratory testing is a cumbersome task. To overcome these limitations, a methodology to simulate the failure of jointed rock mass using the rock-like material, cement mortar, containing a single joint was adopted and its details are presented in this paper. Specifically, the direct shear tests were conducted on artificially prepared jointed rock masses with different joint continuity and undulating angles. The influence of joint continuity and the undulating angle on the shear strength of the nonconsecutive joints was studied. Then, the influence of the normal stress and joint continuity on the deterioration of the mechanical properties of the rock bridge during shearing was analyzed based on the experimental results. A new model for estimating the shear strength of a nonconsecutive jointed rock mass was proposed based on the experimental results and previous studies. The test results show that the smaller the undulating angle and the greater the penetration, the lower the shear strength of the nonconsecutive joint. Besides, the normal stress level and the joint continuity have a significant influence on the weakening of the mechanical properties of the rock bridge. When the normal stress decreases or the joint length increases, the mechanical properties of the rock bridge are significantly weakened. Compared with our estimation of the nonconsecutive joint shear strength based on the original Jennings criterion and the modified Jennings criterion, the calculation results of the newly modified Jennings criterion developed in this study are generally more consistent with the measured values, and thus, they more accurately predict the shear strength of the nonconsecutive jointed rock mass with a regular joint undulating angle.

Jie Hu;术才 李;Hongliang Liu;Liping Li;Shaoshuai Shi;Chengshuai Qin

International Journal of Geomechanics

2020-7-1

The finite element contrast model such as concrete filled steel tube support, U-steel support and hollow steel tube support were established with ANSYS software, combining with engineering practice and relative design scheme of concrete filled steel tube test, respectively analysis their influencing factors and mechanical properties such as support effect, bearing capacity and so on. The economic benefit of each support was been analysised by comprehensive comparison of the material using condition and mechanical performance. The results show that, comparing with traditional U-steel support, retractable concrete filled steel tube support is a new style support with high bearing capacity, a large variety of sizes, higher economic benefit, and hence fit to support the deep soft rock broken jointed rock mass.

Qi Wang;Bei Jiang;术才 李;Han Peng Wang;Wei Teng Li;Zhi Li

2011

A novel visualizing constant pressure penetration grouting diffusion and reinforcement simulation test device was designed. The ordinary Portland cement 42.5 (OPC), microfine Portland cement (MC), microfine sulphoaluminate cement (MSAC), and self-developed effective microfine cement-based grout (EMCG) were selected, and the penetration grouting diffusion and reinforcement test has been performed. The variation rules of diffusion distance and volume under different suspension and grouting pressures were studied, as well as the effects of grouting material, pressure and sand gradation on the reinforcement. The ANOVA method was adopted to determine the dominant factor for grouting effectiveness, and the macroscopic failure modes of reinforcement specimens were obtained. The microscopic reinforcement model of rock-slurry interface and mineral characteristic were analyzed through SEM method, and the core reasons of reinforcement differences caused by different grouts were revealed. The results show that the grouting material and particle percent in slurry were the dominant factors for the groutability of fine sandy stratum, the increase of groutability was not evident with the increase of grouting pressure. The groutability of EMCG slurry was the best, followed by MC and MSAC, and the groutability of OPC slurry was the worst. The strength improvement of reinforcement specimen was better when the sand gradation was finer when suspensions penetrated fully. The 7 d and 28 d strengths of EMCG reinforcement specimen are higher than those of MSAC, MC and OPC, the 7 d of strength of EMCG reinforcement specimen is greater than 70% value of its 28 d strength. The grout is the dominant factor for reinforcement effectiveness, and EMCG is the best while OPC is the worst. After grouting, the dense C-S-H gels produced in EMCG rock-slurry interface can enhance its bonding strength effectively. Finally, improvement suggestions for practical penetration grouting design have been put forward based on three aspects, which are grouts selection, grouting dynamic control and drilling holes layout.

Fei Sha;术才 李;Chun Jin Lin;Ren Tai Liu;庆松 张;Lei Yang;Zhao Feng Li

Yantu Lixue/Rock and Soil Mechanics

2019-11-10

In order to see into stability of rock mass during crack propagation, and the fracture toughness increment of crack by bolt which will prevent propagation of crack, the relationship of shear strength of bolted joint plane and bolting parameters in compressive-shear stress state is set up. Furthermore, sub-crack propagation mechanics model is developed on the basis of catastrophe theory, which is significant for understanding crack propagation process, assessing stability of rockmass, and taking reasonable bolting measures in advance.

术才 李;Weizhong Chen;Weishen Zhu;Shufa Wang

Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

2003-10

The principles of construction process mechanics, energy transformation of surrounding rock and support, and time-space effect of construction have been developed and explained. Some case history studies of time-space effect for construction process for the tunnels or caverns of Jinchuan Nickel Mining, Huainan Coal Mining, Xiaolangdi Hydro-electric Project are presented.

Weishen Zhu;术才 李;Shiwei Bai;Quansheng Liu

Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

2003-10

Pre-stressed anchor cables are widely used in tunnels, slopes and foundation pits. The loss of anchorage force affects the anchoring of pre-stressed anchor cable. The engineering accidents of anchorage failure often occur owing to the loss of anchorage force of pre-stressed anchor cable. The stress state of pre-stressed cable anchor is easily changed and anchor failure leads to engineering accident in water-affluent region. Based on the deformation data, this paper establishes a coupling constitutive model considering soil creep, anchorage force loss of pre-stressed anchor cable and seepage force. Then, the three-dimensional creep equation of soil and relaxation equation of anchoring force loss of pre-stressed anchor cables are deduced. Based on FLAC^3D software, the corresponding procedure is developed to calculate and analyze the soil creep and anchoring force characteristics loss of the above mentioned foundation pit in coastal region. Combined with monitoring data, the above constitutive model is feasible and correct for analyzing anchoring force loss characteristics of pre-stressed anchor cables under seepage condition. The research results provide meaningful theoretical and practical guide for other similar projects.

Can Xie;树忱 李;术才 李;Qi Kai Liao;Shi Sen Zhao

Yantu Lixue/Rock and Soil Mechanics

2017-8-10