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Vacuum preloading is a soft ground improvement method that has been successfully used by geotechnical engineers and specialists to accelerate the rate of consolidation. However, consolidation efficiency is low when dealing with newly reclaimed high-clay content dredger fills because of sludge plugging of the prefabricated vertical drains. In this study, step vacuum preloading was proposed to reinforce a high-clay content dredger fill by applying the vacuum load gradually to consolidate the dredger fill fully and to reduce the migration of fine particles. An indoor simulation test was conducted, and monitoring data were obtained. Results showed that the settlements increased gradually, the pore water pressures and flow velocities decreased over time, and all the changes tended to be stable by the end of the test. The settlements at each stage were more than that at the previous stage, illustrating that changing the method of drainage consolidation in a timely manner, or increasing the vacuum pressure, can more fully consolidate the dredger fill at each stage, thus improving the consolidation efficiency of the dredger fill. The reinforcement effect of the high-clay content dredger fill was also analyzed. The results show that the moisture contents and porosities decreased gradually, the bearing capacity increased gradually in the consolidation process, and each property index of the dredger fill changed with the increase in degree of consolidation, and the regularity of the distribution of the indices showed that obvious siltation did not occur in the consolidation process. Overall, the consolidation efficiency was effectively improved. Thus, the step vacuum preloading method is suitable for high-clay content dredger fills. This method can improve the consolidation efficiency and the uniform reinforcement effect. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of electroacupuncture (EA) at "Jiaji" (EX-B2) at different time points on the expression of OX-42 (a monoclonal antibody with specific expression of complement receptor-3 in spinal microglial cells) and purinergic receptor P2X4 (P2X4) in rats with chronic constriction injury (CCI) of the sciatic nerve, as well as the possible after-effect mechanism of EA analgesia in neuropathic pain., Methods: Sprague-Dawley rats were randomly divided into blank group, model group, immediately after EA group, 0.5-hour after EA group, 1-hour after EA group, 2-hour after EA group, 4-hour after EA group, 12-hour after EA group, and 24-hour after EA group, with 6 rats in each group. The rats in the model group and the EA groups were used to establish a model of CCI-induced neuropathic pain, and those in the immediately after EA group and the 0.5, 1, 2, 4, 12 and 24 hours after EA groups were treated with EA at bilateral L3 and L5 "Jiaji" points for 20 min after 7 d of modeling. Samples were collected immediately and at 0.5, 1, 2, 4, 12, and 24 hours after EA, and for the rats in the blank group and the model group, samples were collected after fixation the rats for 20 min. Heat pain threshold was observed before and after intervention, and immunohistochemistry was used to measure the protein expression of OX-42 and P2X4 in the spinal cord lumbar enlargement., Results: After 7 days of modeling (before intervention), compared with the blank group, the heat pain threshold had a significant reduction in the model group and the EA groups ( P <0.01). Compared with the model group after intervention, the immediately after EA group and the 0.5, 1 and 2 hours after EA groups had a significant increase in heat pain threshold ( P <0.05). Compared with the model group, immediately after EA, the 0.5, 1 and 2 hours after EA groups had a significant reduction in the protein expression of OX-42 ( P <0.01), and immediately after EA, the 0.5 and 1 hour after EA groups had a significant reduction in the protein expression of P2X4 ( P <0.01)., Conclusion: EA at "Jiaji" points can significantly increase heat pain threshold and down-regulate the protein expression of OX-42 and P2X4 in the spinal cord of CCI rats. The analgesic effect can last for 2 h.