Development of a new controlled low strength filling material from the activation of copper slag: Influencing factors and mechanism analysis

2020 ◽  
Vol 246 ◽  
pp. 119060 ◽  
Author(s):  
Wentao Lan ◽  
Aixiang Wu ◽  
Ping Yu
Keyword(s):  
Influencing Factors ◽  
Copper Slag ◽  
Filling Material ◽  
Mechanism Analysis ◽  
Low Strength

scholarly journals Subsidence Control Design Method and Application to Backfill-Strip Mining Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiaojun Zhu ◽  
Feng Zha ◽  
Guangli Guo ◽  
Pengfei Zhang ◽  
Hua Cheng ◽  
...  
Keyword(s):  
Coal Mining ◽  
Influencing Factors ◽  
Recovery Rate ◽  
Design Method ◽  
Control Design ◽  
Resource Recovery ◽  
Design Parameters ◽  
Strip Mining ◽  
Filling Material ◽  
Mining Technology

Intensive and massive coal mining causes a series of geological hazards and environmental problems, especially surface subsidence. At present, two major types of subsidence control technology are applied: backfilling technology and partial mining technology. However, the cost of backfill mining is high and partial mining has a low recovery ratio. Therefore, the backfill-strip mining is used to solve the problems of high cost and shortage of filling materials in coal mines at present. A subsidence control design method of backfill-strip mining was proposed in this paper based on the subsidence control effects and economic benefits. First, the stability of the composite support pillar of the filling body and coal pillars in the backfill-strip mining is analyzed, and the values of the main subsidence influencing factors that include the filling material, the size of the backfilling working face, caving mining face, and residual coal pillar are preliminarily determined. Then, the surface movement and deformation are predicted based on the equivalent superposition probability integral method (PIM). The subsidence influencing factors are optimized and determined by comparing the requirements of the safety fortification index of the antideformation ability of surface buildings, resource recovery rate, and coal mining cost. Finally, the mining scheme design parameters of the backfill-strip mining technology are determined. This method is applied in the subsidence control design of backfill-strip mining in the Ezhuang coal mine. Research results show that backfill-strip mining can ensure the safety of surface buildings, increase the resource recovery rate, and reduce coal mining costs through the reasonable design of this method. This study can provide scientific guidance for subsidence disaster control, prevention, and engineering design in backfill-strip mining.

scholarly journals The mechanism analysis of micro frost heave coarse-grained filling material in the high-speed railway

2016 ◽  
Vol 2 (47) ◽  
pp. 1660-1663 ◽  
Author(s):  
Yang-sheng Ye ◽  
De-goui Cai ◽  
Hong-ye Yan ◽  
Jian-ping Yao ◽  
Qian-li Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Coarse Grained ◽  
Frost Heave ◽  
Filling Material ◽  
Mechanism Analysis ◽  
High Speed Railway

scholarly journals Experimental and Mechanism Analysis of Chlorination and Reduction of Copper Slag

2020 ◽  
Vol 453 ◽  
pp. 012093
Author(s):  
Shuchen Sun ◽  
Qingchun Yu ◽  
Yong Deng ◽  
Xiumin Chen ◽  
Jing Chen ◽  
...  
Keyword(s):  
Copper Slag ◽  
Mechanism Analysis

scholarly journals A Strengthening Mechanism and Influencing Factors of Coal Fly Ash using Microbial-Induced Carbonate Precipitation

2021 ◽  
Author(s):  
Shuaifeng Wu ◽  
Hong Cai ◽  
Ran Wei ◽  
Jianzhang Xiao ◽  
Jun Yan ◽  
...  
Keyword(s):  
Fly Ash ◽  
Calcium Carbonate ◽  
Influencing Factors ◽  
Fine Particles ◽  
Coal Fly Ash ◽  
Carbonate Precipitation ◽  
Filling Material ◽  
Dust Suppression ◽  
Curing Conditions ◽  
Nutrient Salt

Abstract Coal fly ash (CFA) that is discharged from coal-fired power plants has characteristics of fine particles, a small specific gravity and a large pore ratio. The dust suppression and strengthening of CFA is usually carried out by spraying water in the ash storage yard, but this practical approach is unsatisfactory. The strength of the CFA filling material affects the construction safety and operational safety of the ash dams. To carry out effective CFA material utilization and dust-pollution control, this paper applied the microbial-induced carbonate precipitation (MICP) method to enhance the strength of CFA under two curing conditions of natural evaporation (NE) and in a moisture cylinder (MC). The microbial-reaction mechanism, strengthening characteristics and influencing factors were studied. The results show that: 1) the calcium carbonate that is produced by microorganisms in the CFA is calcite, and the calcium-carbonate content increases from 7% to 18.9% and 15.3% under the MC and NE curing conditions, respectively; 2) MICP can improve the CFA strength, and the unconfined compressive strength can be increased by 6.55 times to 97.63 kPa under the MC curing conditions; 3) the solidification strength of CFA varies significantly with the concentration of CaCl2.2H2O and CH4N2O nutrients. The peak stress increases initially and then decreases with an increase in nutrient salt concentration. The optimum nutrient concentration was 0.5 mol/L and 1.0 mol/L for the MC and NE curing conditions, respectively; 4) calcium carbonate that was induced by microbial reaction can reduce the water loss in the ash specimen, and allow the ash surface to form a better water-retention effect, with good prospects for dust suppression.

scholarly journals Numerical investigation on rigid and flexible pipelines embedded in granular and self-compacting materials

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Khalid Abdel-Rahman ◽  
Tim Gerlach ◽  
Martin Achmus
Keyword(s):  
Numerical Model ◽  
Material Behavior ◽  
Filling Material ◽  
Soil System ◽  
Advantages And Disadvantages ◽  
Filling Materials ◽  
Soil Cement ◽  
Flowable Fill ◽  
Low Strength ◽  
Coulomb Failure Criterion

Abstract Self-compacting filling material or controlled low-strength material (CLSM) is a cementitious material which is liquid during filling, and it is used primarily as backfill, e.g., in trenches. Several products are currently used as CLSM such as flowable fill, controlled density fill, flowable mortar and low-strength plastic soil–cement. The low-strength requirement is necessary to allow for future excavation of CLSM. A two-dimensional numerical model was developed using the finite element system ABAQUS. In this model, the material behavior of granular soil and CLSM is described using an elasto-plastic constitutive model with Mohr–Coulomb failure criterion. Rigid and flexible pipes were modeled once embedded in sandy soil and once embedded in self-compacting material. The numerical model allows the modeling of the effect of hardening process on the overall behavior of the pipe–soil system. The main objective of this study is to investigate the behavior of rigid and flexible pipelines embedded in CLSM as a filling material numerically and to show advantages and disadvantages in comparison with the presently widely used filling materials like sand.

scholarly journals Mechanical Mechanism Analysis and Influencing Factors of Subway Cross Passage Construction

2019 ◽  
Vol 16 (6) ◽  
Author(s):  
Wu Ke ◽  
Cui Shuaishuai ◽  
Zhang Qianjin ◽  
Zhang Zheng ◽  
Zhao Jiahui ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Mechanism Analysis

scholarly journals Mechanical properties of copper slag waste based CLSM mixtures

2019 ◽  
Author(s):  
Roman Jaskulski ◽  
Wojciech Kubissa
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Copper Slag ◽  
Strength Tests ◽  
Low Strength ◽  
Slag Waste

The article presents the results of investigations of the compressive strength of controlled low-strength materials (CLSM) prepared with the use of copper slag waste as a filler. Eighteen mixtures were made of which part with sole copper slag waste, part with sand which served as reference and mixtures in which half of the filler was sand and half the copper slag waste. Part of them was prepared with 60 kg/m3 of cement and another part with 40 kg/m3 of cement. As a supplementary binder conventional fly ash was used. The aim was to recognie the feasibility of this type of material using copper slag waste as filler. Compressive strength tests were performed on the specimens in form of 40×40×160 mm bars. The tests showed that after meeting certain conditions regarding the composition of the mixture, the copper slag waste can be used as a filler in CLSM. The compressive strength values after 180 days not exceeded 1.60 MPa which is a very good result for this kind of material.

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