The amount of muddy soil generated from various kinds of construction sites is always problematic. It is very difficult to treat muddy soil because of its low strength and high water content. But, the reuse of muddy s...The amount of muddy soil generated from various kinds of construction sites is always problematic. It is very difficult to treat muddy soil because of its low strength and high water content. But, the reuse of muddy soil is necessary to reduce the total amount of industrial wastes. Surplus concrete is also in a similar situation. Coarse and fine aggregates are removed from surplus concrete as an intermediate treatment, however, concrete sludge still remains. The authors propose a reuse method that involves the muddy soil being mixed with concrete sludge as an improvement material. The possibility of the utilization of concrete sludge was investigated through laboratory experiments. As a result, it was found that the unconfined compressive strength of the improved soil mixed with concrete sludge increased as the curing proceeded.展开更多
Conventional PCC pile technique has been widely used as embankment piles for highway construction in China. To further improve the PCC pile capacity, the expansive concrete technique has been applied to the PCC pile t...Conventional PCC pile technique has been widely used as embankment piles for highway construction in China. To further improve the PCC pile capacity, the expansive concrete technique has been applied to the PCC pile to replace the normal concrete recently. The use of expansive concrete for the PCC pile could increase the pile diameter as well as the contact pressure at the pile-soil interface due to the expansion process of concrete, which allows the improved PCC pile to provide higher capacity than the conventional PCC pile. This paper presents a theoretical model for the new improved PCC pile using expansive concrete technique. The model is formulated by assuming the PCC pile installation process as large strain undrained cylindrical cavity expansion and the subsequent pile shaft expansion combined with soil consolidation process is simulated by the small strain cylindrical cavity expansion combined with strain-controlled consolidation. Then, similarity solution technique is used to solve the problem of cavity expansion in modified cam Clay （MCC） model, while the strain-controlled consolidation is calculated through the finite difference method （FDM）. Subsequently, the suitability of the cavity expansion solution in the interpretation of the PCC pile installation is verified by comparing the calculated excess pore pressure with the measured value in an instrumented field test. The stress changes and excess pore pressure during the PCC pile installation and subsequent pile shaft expansion are investigated by means of parametric study. The proposed theoretical model first reveals and quantifies the fundamental mechanism of the PCC pile using expansive concrete technique and it provides a theoretical basis for developing design methods of the new improved PCC pile in the future.展开更多
文摘The amount of muddy soil generated from various kinds of construction sites is always problematic. It is very difficult to treat muddy soil because of its low strength and high water content. But, the reuse of muddy soil is necessary to reduce the total amount of industrial wastes. Surplus concrete is also in a similar situation. Coarse and fine aggregates are removed from surplus concrete as an intermediate treatment, however, concrete sludge still remains. The authors propose a reuse method that involves the muddy soil being mixed with concrete sludge as an improvement material. The possibility of the utilization of concrete sludge was investigated through laboratory experiments. As a result, it was found that the unconfined compressive strength of the improved soil mixed with concrete sludge increased as the curing proceeded.
基金supported by the National Natural Science Foundation of China(Grant No.51420105013)
文摘Conventional PCC pile technique has been widely used as embankment piles for highway construction in China. To further improve the PCC pile capacity, the expansive concrete technique has been applied to the PCC pile to replace the normal concrete recently. The use of expansive concrete for the PCC pile could increase the pile diameter as well as the contact pressure at the pile-soil interface due to the expansion process of concrete, which allows the improved PCC pile to provide higher capacity than the conventional PCC pile. This paper presents a theoretical model for the new improved PCC pile using expansive concrete technique. The model is formulated by assuming the PCC pile installation process as large strain undrained cylindrical cavity expansion and the subsequent pile shaft expansion combined with soil consolidation process is simulated by the small strain cylindrical cavity expansion combined with strain-controlled consolidation. Then, similarity solution technique is used to solve the problem of cavity expansion in modified cam Clay （MCC） model, while the strain-controlled consolidation is calculated through the finite difference method （FDM）. Subsequently, the suitability of the cavity expansion solution in the interpretation of the PCC pile installation is verified by comparing the calculated excess pore pressure with the measured value in an instrumented field test. The stress changes and excess pore pressure during the PCC pile installation and subsequent pile shaft expansion are investigated by means of parametric study. The proposed theoretical model first reveals and quantifies the fundamental mechanism of the PCC pile using expansive concrete technique and it provides a theoretical basis for developing design methods of the new improved PCC pile in the future.
