Effect of Vertical Flow on Consolidation Degree of Foundation with Vertical Drains in Large-Strain Consolidation Theory

Yupeng Cao,Jianwen Ding,Rui Zhang,Guizhong Xu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9

Vertical flow has an important effect on consolidation rate of ultra-soft soil, but the influence law and influence level on the degree of large-strain consolidation have not been quantitatively evaluated. Based on the negative axisymmetric large strain consolidation (NALSC) model, the variation laws of calculation error of consolidation degree ignoring vertical flow with consolidation time and strain are studied under different values of H/re (ratio of soil thickness to influence radius), w0/wL (ratio of initial water content to liquid limit) and kh/kv (ratio of horizontal permeability coefficient to vertical permeability coefficient). Taking 10% as the error threshold, the H/re values ignoring vertical flow are given, and the difference between them in the theories of large-strain and small-strain is discussed. The results show that the effect of vertical flow on degree of stress consolidation (Up) is greater than degree of strain consolidation (Us). The H/re values neglecting the effect of vertical flow on the degree of consolidation in large-strain theory are less than those in small-strain theory. The calculation errors affected by vertical flow decrease with the increase of H/re and kh/kv. Error of Us affected by vertical flowdecreases, whereas error of Up increases with the increase of w0/wL. The effect of vertical flow on the degree of consolidation is greater when well resistance is considered.

A Large-Strain Vacuum-Assisted Radial Consolidation Model for Dredged Sludge considering Lateral Deformation

Yupeng Cao,Jing Zhang,Jianwen Xu,Guizhong Xu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12

A calculation model has been developed for large-strain radial consolidation incorporating lateral deformation in order to solve the problem of poor consolidation prediction for dredged sludge at high water content in vacuum preloading process. The differential solution for the proposed model is given, considering the effect of initial water content on the compression behavior. The model is suitable for unconsolidated soil and normally consolidated soil, which can take into account such factors as lateral deformation, varying compressibility and permeability coefficients, smearing effect, self-weight stress, negative pressure attenuation along the depth, etc. The proposed model is verified by comparing it with other existing theoretical solutions. Poisson's ratio (v) is used to reflect the influence of lateral deformation on soil consolidation. The results show that lateral deformation has an important influence on soil consolidation degree, especially on consolidation degree defined by stress (Up). The consolidation rate increases with the increase of v. The traditional equal-strain solution overestimates the consolidation rate of foundation. At the same normalized elevation, the void ratio increases while the excess pore water pressure decreases with the increase of v.

Effect of Clogging on Large Strain Consolidation with Prefabricated Vertical Drains by Vacuum Pressure

Yupeng Cao,Jianwen Xu,Xia Bian,Guizhong Xu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.10

Clogging will inevitably occur while using vacuum preloading method to process super-soft soils with high water content. How to quantitatively evaluate the effect of clogging on the consolidation behavior is a key issue to be solved. Based on NALSC (negative axisymmetric large-strain consolidation) model, considering the “internal clogging” and the “external clogging”, a calculation method by using parameter “clogging rate” to reflect clogging problem is proposed for single-well consolidation theory. Effects of clogging rate and clogging occurred time on Us (degree of consolidation defined by strain) and Up (degree of consolidation defined by stress) are investigated. Differences of the effect of clogging on consolidation degree are determined between large-strain and small-strain consolidation theory. The results show that, the larger the clogging rate, the smaller the degree of consolidation of the soil at the same consolidation time. Effect of clogging on Up is greater than Us. The earlier the clogging occurs, the smaller the degree of consolidation at the same clogging rate. Influences on the degree of consolidation for large-strain and small-strain theory are the same. Consolidation rate of soil is determined to a certain extent by the “generalized clogging parameter μ”. The “external clogging” has a greater influence on the degree of consolidation than the “internal clogging” at the same clogging rate.

원자력발전 수용성의 영향요인에 관한 연구: 위험인식과 정부신뢰의 매개효과를 중심으로

조우봉 ( Cao Yupeng ),목진휴 ( Mok Jin W. ) 국민대학교 사회과학연구소 2016 社會科學硏究 Vol.29 No.1

후쿠시마 원자력발전소 사고 이후 국민들의 위험인식이 높아지고 있는 상황에서 잠재적위험이 존재하는 원자력을 전력생산의 동력으로 국민들이 수용할 수 있도록 하는 방안의모색에 정책적 초점이 주어져 있다. 이에 본 연구는 원자력발전 수용성에 영향을 줄 수 있는 요인들을 알아봄과 동시에 이러한 요인들과 수용성과의 관계에서 매개적 영향을 초래할것으로 믿어지는 요인들을 파악하고 이들의 정책적 의미를 찾는데 목적을 두고 있다. 일반국민들의 원자력에 대한 인식조사결과에 따르면, 원자력과 관련된 지식수준이 높으면 원자력발전에 대한 수용성이 높게 나타났으나 원자력정책에 대한 만족여부는 원자력발전에 대한 수용성에 영향을 초래하지 않는 것으로 검증되었다. 반면에 원자력에 대한 위험인식은 지식수준과 수용성의 관계를 매개하지 않으나 정부에 대한 신뢰는 정책만족도와 정책수용의 관계에서 매개효과를 보인다. 특히, 정부를 신뢰하면 할수록 원자력정책에 대한 만족도는 추가원자력 발전소 건설에 대해 긍정적인 영향을 초래하는 것으로 확인되었다. 이러한점은 정부 정책에 대한 국민들의 수용도를 높이기 위해선 국민들이 정부를 신뢰할 수 있도록 해야 한다는 기존의 연구결과를 재차 확인하는 것이며 특히 정부가 원자력 발전소의 추가건설을 위한 노력에는 국민들이 정부의 업무에 대한 전반적인 신뢰가 따라야 한다는 점을 지적하고 있다. This study aims to investigate the mediating role of public trust and risk perception to the relationship between the public acceptance and knowledge level and between the public acceptance and the policy satisfaction. According to the results using the public survey on the public perception on the nuclear issues, the public generally accept the government’s effort to expand nuclear capacity in electricity production and those who have higher level of trust on the government tend to promote the relationship between the policy satisfaction and policy acceptance, though risk perception not showing any mediating effect to the knowledge level and policy acceptance relationship. What this means is to confirm those existing studies that emphasize the role of the trust in government, and to suggest more prudent effort by the government in search of means to promote its level.

The Design of a Guide Device with Multi-Function to Aid Travel for Blind Person

Jiayin Song,Wenlong Song,Yupeng Cheng,Xuefu Cao 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.4

A design method of a guide device with multi-function presented in this paper, the multi-function contents of obstacle avoidance, azimuth guidance, banknote recognition and time broadcast. The hardware system of the guide device based on single-chip system STC89C52 and peripheral added eight expansion units: power supply unit, key input unit, ultrasonic detection unit, azimuth guidance unit, banknote recognition unit, clock Unit, phonetic unit and display unit. The functions were tested and results show that the device is suitable for sunny conditions whose best setting distance range is between 700mm to 1600mm and direction function is good showing in open environment, while the function of currency recognition has some limitations because of color identification. Comprehensive consideration the device can meet the blind person’s basic travel demand and has the characteristics of low-cost and stable performance.

Prevalence of Intracranial Aneurysm in Patients with Aortopathy: A Systematic Review with Meta-Analyses

Xinyu Yu,Liangtao Xia,Qingqing Jiang,Yupeng Wei,Xiang Wei,Shiyi Cao 대한뇌졸중학회 2020 Journal of stroke Vol.22 No.1

Background and Purpose Patients with aortic disease might have an increased risk of intracranial aneurysm (IA). We conducted this research to assess the prevalence of IA in patients with aortopathy, considering the impact of gender, age, and cardiovascular risk factors. Methods We searched PubMed and Scopus from inception to August 2019 for epidemiological studies reporting the prevalence of IA in patients with aortopathy. Random-effect meta-analyses were performed to calculate the overall prevalence, and the effect of risk factors on the prevalence was also evaluated. Anatomical location of IAs in patients suffered from distinct aortic disease was extracted and further analyzed. Results Thirteen cross-sectional studies involving 4,041 participants were included in this systematic review. We reported an estimated prevalence of 12% (95% confidence interval [CI], 9% to 14%) of IA in patients with aortopathy. The pooled prevalence of IA in patients with bicuspid aortic valve, coarctation of the aorta, aortic aneurysm, and aortic dissection was 8% (95% CI, 6% to 10%), 10% (95% CI, 7% to 14%), 12% (95% CI, 9% to 15%), and 23% (95% CI, 12% to 34%), respectively. Gender (female) and smoking are risk factors related to an increased risk of IA. The anatomical distribution of IAs was heterogeneously between participants with different aortic disease. Conclusions According to current epidemiological evidence, the prevalence of IA in patients with aortic disease is quadrupled compared to that in the general population, which suggests that an early IA screening should be considered among patients with aortic disease for timely diagnosis and treatment of IA.