Soil responds to cavity expansion is inherently rate-dependent,especially in the case of fine-grained soils.To better understand such rate effects,self-boring pressuremeter tests were conducted on Kunming peaty soil w...Soil responds to cavity expansion is inherently rate-dependent,especially in the case of fine-grained soils.To better understand such rate effects,self-boring pressuremeter tests were conducted on Kunming peaty soil within a strain rate range of 0.1%/min to 5.0%/min.The results showed a clear dependence of cavity pressure and excess pore pressure(EPP)on strain ratesdboth increased with higher rates for a given radial displacement.In light of the experimental results,three cases of cylindrical cavity expansion were investigated using the finite element method and analytical method,partially drained expansion in Modified Cam-Clay(MCC)soil,and undrained and partially drained expansion in elastoviscoplastic(EVP)soil.The EVP behavior was and modeled using the MCC model and the overstress viscoplastic theory.The results indicated that over the strain rate range of 0.0001%/min and 50%/min,the rate response of cavity pressure for the case of partially drained expansion in MCC soil(permeability coefficient ranging from 5×10^(-6) m/s to 2.5×10^(-11) m/s)is not obvious,while the EPP response during undrained expansion in EVP soil shows rate-independent.Only the partially drained solution for cavity expansion in EVP soil captured the rate-sensitive responses of both cavity pressure and EPP,confirmed by the pressuremeter tests on the Kunming peaty soil,Saint-Herblain clay,and Burswood clay.This suggests that the rate effect results from a combination of drainage-related and time-dependent soil behavior.Parametric studies further demonstrated that both viscous behavior and the overconsolidation ratio significantly influence cylindrical cavity expansion response,and the drainage conditions during expansion can be assessed using a nondimensional velocity.展开更多
Objectives We did a retrospective study to summarize the surgical experience of anomalous pulmonary venous drainage (APVD) correction and discuss effective way of improving the surgical outcome. Methods From January 1...Objectives We did a retrospective study to summarize the surgical experience of anomalous pulmonary venous drainage (APVD) correction and discuss effective way of improving the surgical outcome. Methods From January 1985 to May 2008, 127 patients [56 men and 71 women, aged 14-55 years with an average of (26.79±10.62) years] with APVD underwent surgical treatments. Among them, 13 patients had simple partial APVD with intact atrial septum, 104 patients had partial APVD with atrial septal defect and 10 patients had total APVD. Seventy-one patients of them accompanied with other cardiac anomalies which were also corrected in their operations. Results One early operative death due to severe low cardiac output syndrome (LCOS) developed postoperatively, which resulted in a mortality rate of 0.78%. Among other patients, 10 patients complicated with LCOS, 11 patients with arrhythmia, 7 patients with acute renal failure and 4 patients with poor wound healing, all discharged from hospital after treatment. Postoperative echocardiography reexamination revealed 1 case of mild residual shunt in atrial septum but without pulmonary vein stenosis. Conclusion For right atrial and ventricle enlarged patients with or without pulmonary hypertension, surgeons should be vigilance of accompanied APVD whether atrial septal defects exist or not. As long as no contraindications are found, surgical treatment should be performed once accurate diagnosis is obtained.展开更多
基金The financial support of the National Natural Science Foundation of China(Grant Nos.41972293,42272337)the Science Fund for Distinguished Young Scholars of Hubei Province(Grant No.2023AFA078)are gratefully acknowledged.
文摘Soil responds to cavity expansion is inherently rate-dependent,especially in the case of fine-grained soils.To better understand such rate effects,self-boring pressuremeter tests were conducted on Kunming peaty soil within a strain rate range of 0.1%/min to 5.0%/min.The results showed a clear dependence of cavity pressure and excess pore pressure(EPP)on strain ratesdboth increased with higher rates for a given radial displacement.In light of the experimental results,three cases of cylindrical cavity expansion were investigated using the finite element method and analytical method,partially drained expansion in Modified Cam-Clay(MCC)soil,and undrained and partially drained expansion in elastoviscoplastic(EVP)soil.The EVP behavior was and modeled using the MCC model and the overstress viscoplastic theory.The results indicated that over the strain rate range of 0.0001%/min and 50%/min,the rate response of cavity pressure for the case of partially drained expansion in MCC soil(permeability coefficient ranging from 5×10^(-6) m/s to 2.5×10^(-11) m/s)is not obvious,while the EPP response during undrained expansion in EVP soil shows rate-independent.Only the partially drained solution for cavity expansion in EVP soil captured the rate-sensitive responses of both cavity pressure and EPP,confirmed by the pressuremeter tests on the Kunming peaty soil,Saint-Herblain clay,and Burswood clay.This suggests that the rate effect results from a combination of drainage-related and time-dependent soil behavior.Parametric studies further demonstrated that both viscous behavior and the overconsolidation ratio significantly influence cylindrical cavity expansion response,and the drainage conditions during expansion can be assessed using a nondimensional velocity.
基金supported by Natural Science Foundation of Guangdong Province ( No.5001161)Medical Science Foundation of Guangdong Province (No.A2005049)
文摘Objectives We did a retrospective study to summarize the surgical experience of anomalous pulmonary venous drainage (APVD) correction and discuss effective way of improving the surgical outcome. Methods From January 1985 to May 2008, 127 patients [56 men and 71 women, aged 14-55 years with an average of (26.79±10.62) years] with APVD underwent surgical treatments. Among them, 13 patients had simple partial APVD with intact atrial septum, 104 patients had partial APVD with atrial septal defect and 10 patients had total APVD. Seventy-one patients of them accompanied with other cardiac anomalies which were also corrected in their operations. Results One early operative death due to severe low cardiac output syndrome (LCOS) developed postoperatively, which resulted in a mortality rate of 0.78%. Among other patients, 10 patients complicated with LCOS, 11 patients with arrhythmia, 7 patients with acute renal failure and 4 patients with poor wound healing, all discharged from hospital after treatment. Postoperative echocardiography reexamination revealed 1 case of mild residual shunt in atrial septum but without pulmonary vein stenosis. Conclusion For right atrial and ventricle enlarged patients with or without pulmonary hypertension, surgeons should be vigilance of accompanied APVD whether atrial septal defects exist or not. As long as no contraindications are found, surgical treatment should be performed once accurate diagnosis is obtained.
