Traditional stabilization of backfilling material is done by using Portland cement. However, the high price of cement forced mining engineer s to seek cheaper binding materials. Fly ash, which is the indus- trial wast...Traditional stabilization of backfilling material is done by using Portland cement. However, the high price of cement forced mining engineer s to seek cheaper binding materials. Fly ash, which is the indus- trial wast e from thermal power plant, possess the potential activity of jellification, and can b e used in cemented fill as a partial substitute for cement to reduce the fill co s t. Tests were done during the past few years in Xinqiao Pyrite Mine and Phoenix Copper Mine to determine the technology parameters and the suitable content of f ly ash. Specimens with different cement/fly/ash tailings (sands) ratios were tes ted to obtain the strength values of the fill mass based on the analyses of both the chemical composition and physical and mechanical properties of fly ash . The compressive strength of specimens with a ratio of 1∶2∶8 (cement to fly ash to tailings ) can reach 2 MPa after 90 d curing, totally meeting the requiremen t of artificial pillar and reducing the fill cost by 20%-30%.展开更多
An experimental study on the seismic performance of recycled concrete-filled square steel tube （RCFST） columns is carried out. Six specimens were designed and tested under constant axial compression and cyclic later...An experimental study on the seismic performance of recycled concrete-filled square steel tube （RCFST） columns is carried out. Six specimens were designed and tested under constant axial compression and cyclic lateral loading. Two parameters, replacement percentage of recycled coarse aggregate （RCA） and axial compression level, were considered in the test. Based on the experimental data, the hysteretic loops, skeleton curves, ductility, energy dissipation capacity and stiffness degradation of RCFST columns were analyzed. The test results indicate that the failure modes of RCFST columns are the local buckling of the steel tube at the bottom of the columns, and the hysteretic loops are full and their shapes are similar to normal CFST columns. Furthermore, the ductility coefficient of all specimens are close to 3.0, and the equivalent viscous damping coefficient corresponding to the ultimate lateral load ranges from 0.323 to 0.360, which demonstrates that RCFST columns exhibit remarkable seismic performance.展开更多
目的探讨瘤体刮除骨水泥填充保膝手术与瘤段切除肿瘤型假体置换治疗膝关节周围骨巨细胞瘤的临床疗效。方法选取膝关节周围骨巨细胞瘤患者,将采用瘤段切除肿瘤型假体置换术治疗的患者纳入至置换组,将瘤体刮除骨水泥填充保膝手术治疗的患...目的探讨瘤体刮除骨水泥填充保膝手术与瘤段切除肿瘤型假体置换治疗膝关节周围骨巨细胞瘤的临床疗效。方法选取膝关节周围骨巨细胞瘤患者,将采用瘤段切除肿瘤型假体置换术治疗的患者纳入至置换组,将瘤体刮除骨水泥填充保膝手术治疗的患者纳入至保膝组。置换组26例,保膝组34例。收集两组患者围术期指标、国际骨与软组织肿瘤协会保肢评分(musculo skeletal tumor society,MSTS)、美国纽约特种外科医院评分(hospital for special surgery,HSS)、复发情况,单因素分析影响骨巨细胞瘤术后复发的因素。结果保膝组手术时间明显短于置换组,P<0.05,保膝组患者术中出血量、住院费用均明显少于置换组,P<0.05,但两组患者住院时间比较,P>0.05。术前两组MSTS评分、HSS评分比较,P>0.05,术后6个月及末次随访,保膝组MSTS评分、HSS评分均更高,P<0.05。通过末次随访发现,复发12例(20.00%),未复发患者48例(80.00%)。单因素分析得出影响骨巨细胞瘤术后复发的因素为Campanacci分级和肿瘤体积(P<0.05)。结论瘤体刮除骨水泥填充保膝手术治疗膝关节周围骨巨细胞瘤较瘤段切除肿瘤型假体置换术疗效更优,其复发可能与病理分级或肿瘤体积相关。展开更多
文摘Traditional stabilization of backfilling material is done by using Portland cement. However, the high price of cement forced mining engineer s to seek cheaper binding materials. Fly ash, which is the indus- trial wast e from thermal power plant, possess the potential activity of jellification, and can b e used in cemented fill as a partial substitute for cement to reduce the fill co s t. Tests were done during the past few years in Xinqiao Pyrite Mine and Phoenix Copper Mine to determine the technology parameters and the suitable content of f ly ash. Specimens with different cement/fly/ash tailings (sands) ratios were tes ted to obtain the strength values of the fill mass based on the analyses of both the chemical composition and physical and mechanical properties of fly ash . The compressive strength of specimens with a ratio of 1∶2∶8 (cement to fly ash to tailings ) can reach 2 MPa after 90 d curing, totally meeting the requiremen t of artificial pillar and reducing the fill cost by 20%-30%.
基金the National Natural Science Foundation of China under Grant Nos.51268004 and 51578163the Guangxi Science and Technology Key Project under Grant No.12118023-3
文摘An experimental study on the seismic performance of recycled concrete-filled square steel tube （RCFST） columns is carried out. Six specimens were designed and tested under constant axial compression and cyclic lateral loading. Two parameters, replacement percentage of recycled coarse aggregate （RCA） and axial compression level, were considered in the test. Based on the experimental data, the hysteretic loops, skeleton curves, ductility, energy dissipation capacity and stiffness degradation of RCFST columns were analyzed. The test results indicate that the failure modes of RCFST columns are the local buckling of the steel tube at the bottom of the columns, and the hysteretic loops are full and their shapes are similar to normal CFST columns. Furthermore, the ductility coefficient of all specimens are close to 3.0, and the equivalent viscous damping coefficient corresponding to the ultimate lateral load ranges from 0.323 to 0.360, which demonstrates that RCFST columns exhibit remarkable seismic performance.
文摘目的探讨瘤体刮除骨水泥填充保膝手术与瘤段切除肿瘤型假体置换治疗膝关节周围骨巨细胞瘤的临床疗效。方法选取膝关节周围骨巨细胞瘤患者,将采用瘤段切除肿瘤型假体置换术治疗的患者纳入至置换组,将瘤体刮除骨水泥填充保膝手术治疗的患者纳入至保膝组。置换组26例,保膝组34例。收集两组患者围术期指标、国际骨与软组织肿瘤协会保肢评分(musculo skeletal tumor society,MSTS)、美国纽约特种外科医院评分(hospital for special surgery,HSS)、复发情况,单因素分析影响骨巨细胞瘤术后复发的因素。结果保膝组手术时间明显短于置换组,P<0.05,保膝组患者术中出血量、住院费用均明显少于置换组,P<0.05,但两组患者住院时间比较,P>0.05。术前两组MSTS评分、HSS评分比较,P>0.05,术后6个月及末次随访,保膝组MSTS评分、HSS评分均更高,P<0.05。通过末次随访发现,复发12例(20.00%),未复发患者48例(80.00%)。单因素分析得出影响骨巨细胞瘤术后复发的因素为Campanacci分级和肿瘤体积(P<0.05)。结论瘤体刮除骨水泥填充保膝手术治疗膝关节周围骨巨细胞瘤较瘤段切除肿瘤型假体置换术疗效更优,其复发可能与病理分级或肿瘤体积相关。
