Permeation grouting is widely applied for its low grouting pressure and minor disturbance to the stratum in grouting engineering, especially in engineering with strict requirements on ground settlement. However, perme...Permeation grouting is widely applied for its low grouting pressure and minor disturbance to the stratum in grouting engineering, especially in engineering with strict requirements on ground settlement. However, permeation grouting theory lags behind compared with other engineering disciplines, and the theoretical formulas now available cannot accurately be used to guide grouting engineering design and predict the cost and effects of grouting due to many factors affecting grout permeation in stratum. In this study, permeation grouting experiment devices were independently manufactured with the characteristics of easily controlling grouting pressure, simulating sandy strata grout, and detecting grouting effect. Using a uniform design, the sand consolidation agent, as grouting material, its spread in Shenyang sandy strata was tested with these experiment devices. The quantitative relations between grouting factors （grouting pressure, strata parameters, water-sand consolidation agent ratio） and grouting effects （grout spread radius, gell strength, grout amount） are obtained with regression analysis, and the influence degree of grouting factors on grouting effects is studied.展开更多
Modified cable bolts are commonly used in underground mines due to their superior performance in preventing bed separation when compared with plain strands. To better test the axial performance of a wide range of cabl...Modified cable bolts are commonly used in underground mines due to their superior performance in preventing bed separation when compared with plain strands. To better test the axial performance of a wide range of cable bolts,a new laboratory short encapsulation pull test(LSEPT) facility was developed. The facility simulates the interaction between cable bolts and surrounding rock mass,using artificial rock cylinders with a diameter of 300 mm in which the cable bolt is grouted. Furthermore,the joint where the load is applied is left unconstrained to allow shear slippage at the cable/grout or grout/rock interface.Based on this apparatus,a series of pull tests were undertaken using the MW9 modified bulb cable bolt.Various parameters including embedment length,test material strength and borehole size were evaluated. It was found that within a limited range of 360 mm,there is a linear relationship between the maximum bearing capacity of the cable bolt and embedment length. Beyond 360 mm,the peak capacity continues to rise but with a much lower slope. When the MW9 cable bolt was grouted in a weak test material,failure always took place along the grout/rock interface. Interestingly,increasing the borehole diameter from 42 to 52 m in weak test material altered the failure mode from grout/rock interface to cable/grout interface and improved the performance in terms of both peak and residual capacity.展开更多
In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatograp...In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatographic separation was performed on a C18 （150 min×4.6 mm） column utilizing gradient elution profile and a mobile phase consisting of （A） water and （B） acetonitrile. The calibration curve, with a great correlation coefficient greater than 0.998, was linear over the range of 1.0-30.0 μg/mL for ginsenoside Rgl, 0.5-15.0 μg/mL for ginsenoside Re, and 0.5-200.0 μg/mL for ginsenoside Rb1. The intra- and inter-day precisions for three ginsenosides （Rg1, Re, Rb1） were all less than 6.0%, and average recovery, examined at three concentration levels, ranged from 96.1% to 118.6%. The samples was stable within 24 h at 4 ℃ storage, and 30 d at -20 ℃ storage with three freeze-thaw-assay cycles. The low limits of quantification （LOQ） were 1.0, 0.5 and 0.5 μg/mL for Rg1, Re and Rb1, respectively. Taken together, the newly developed method was successfully applied to study the pharmacokinetics of ginsenoside Rg1, Re and Rb1 in rat plasma after intravenous administration of SHENMAI injection （SMI）.展开更多
基金Supported by the National Science and Technology Support Plan of 12th Five-year Plan （2012BAK24B00, 2012BAK24B0104） the National Natural Science Foundation of China （51204029） the Fundamental Research Funds of Chinese Ministry of Education （N110301003）
文摘Permeation grouting is widely applied for its low grouting pressure and minor disturbance to the stratum in grouting engineering, especially in engineering with strict requirements on ground settlement. However, permeation grouting theory lags behind compared with other engineering disciplines, and the theoretical formulas now available cannot accurately be used to guide grouting engineering design and predict the cost and effects of grouting due to many factors affecting grout permeation in stratum. In this study, permeation grouting experiment devices were independently manufactured with the characteristics of easily controlling grouting pressure, simulating sandy strata grout, and detecting grouting effect. Using a uniform design, the sand consolidation agent, as grouting material, its spread in Shenyang sandy strata was tested with these experiment devices. The quantitative relations between grouting factors （grouting pressure, strata parameters, water-sand consolidation agent ratio） and grouting effects （grout spread radius, gell strength, grout amount） are obtained with regression analysis, and the influence degree of grouting factors on grouting effects is studied.
文摘Modified cable bolts are commonly used in underground mines due to their superior performance in preventing bed separation when compared with plain strands. To better test the axial performance of a wide range of cable bolts,a new laboratory short encapsulation pull test(LSEPT) facility was developed. The facility simulates the interaction between cable bolts and surrounding rock mass,using artificial rock cylinders with a diameter of 300 mm in which the cable bolt is grouted. Furthermore,the joint where the load is applied is left unconstrained to allow shear slippage at the cable/grout or grout/rock interface.Based on this apparatus,a series of pull tests were undertaken using the MW9 modified bulb cable bolt.Various parameters including embedment length,test material strength and borehole size were evaluated. It was found that within a limited range of 360 mm,there is a linear relationship between the maximum bearing capacity of the cable bolt and embedment length. Beyond 360 mm,the peak capacity continues to rise but with a much lower slope. When the MW9 cable bolt was grouted in a weak test material,failure always took place along the grout/rock interface. Interestingly,increasing the borehole diameter from 42 to 52 m in weak test material altered the failure mode from grout/rock interface to cable/grout interface and improved the performance in terms of both peak and residual capacity.
基金Science and Technology Research project of Heilongjiang Province Department of Education(Grant No.12541740)
文摘In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatographic separation was performed on a C18 （150 min×4.6 mm） column utilizing gradient elution profile and a mobile phase consisting of （A） water and （B） acetonitrile. The calibration curve, with a great correlation coefficient greater than 0.998, was linear over the range of 1.0-30.0 μg/mL for ginsenoside Rgl, 0.5-15.0 μg/mL for ginsenoside Re, and 0.5-200.0 μg/mL for ginsenoside Rb1. The intra- and inter-day precisions for three ginsenosides （Rg1, Re, Rb1） were all less than 6.0%, and average recovery, examined at three concentration levels, ranged from 96.1% to 118.6%. The samples was stable within 24 h at 4 ℃ storage, and 30 d at -20 ℃ storage with three freeze-thaw-assay cycles. The low limits of quantification （LOQ） were 1.0, 0.5 and 0.5 μg/mL for Rg1, Re and Rb1, respectively. Taken together, the newly developed method was successfully applied to study the pharmacokinetics of ginsenoside Rg1, Re and Rb1 in rat plasma after intravenous administration of SHENMAI injection （SMI）.
