Effect of Artesian Pressure on Consolidation Behavior of Drainage-Installed Marine Clay Deposit

Pradhan

et al. 2020

Self Cite

Purpose The consolidation behavior of prefabricated vertical drain (PVD)-installed soft deposits mainly depends on the PVD performance. The purpose of this study is to propose a numerical solution for the consolidation of PVD-installed soft soil using the large-strain theory, in which the reduction of discharge capacity of PVD according to depth and time is simultaneously considered. Design/methodology/approach The proposed solution also takes into account the general constitute relationship of soft soil. Subsequently, the proposed solution is applied to analyze and compare with the monitoring data of two cases, one is the experimental test and another is the test embankment in Saga airport. Findings The results show that the reduction of PVD discharge capacity according to depth and time increased the duration required to achieve a certain degree of consolidation. The consolidation rate is more sensitive to the reduction of PVD discharge capacity according to time than that according to the depth. The effects of the reduction of PVD discharge capacity according to depth are more evident when PVD discharge capacity decreases. The predicted results using the proposed numerical solution were validated well with the monitoring data for both cases in verification. Research limitations/implications In this study, the variation of PVD discharge capacity is only considered in one-dimensional consolidation. However, it is challenging to implement a general expression for discharge capacity variation according to time in the two-dimensional numerical solution (two-dimensional plane strain model). This is the motivation for further study. Practical implications A geotechnical engineer could use the proposed numerical solution to predict the consolidation behavior of the drainage-improved soft deposit considering the PVD discharge capacity variation. Originality/value The large-strain consolidation of PVD-installed soft deposits could be predicted well by using the proposed numerical solution considering the PVD discharge capacity variations according to depth and time.

Section: Effects Of Initial Effective Stress Variation In Soft Depositssupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Large-strain consolidation analysis of PVD-installed soft soil considering the discharge capacity variation according to depth and time

Pradhan

et al. 2020

Self Cite

“…Bấc thấm (PVD) kết hợp với gia tải trước hoặc bơm hút chân không thường được sử dụng trong kỹ thuật gia cố nền đất yếu nhằm tăng tốc độ cố kết và cường độ của nền đất yếu [1][2][3][4][5][6][7]. Trong quá trình cố kết của nền đất yếu, nước lỗ rỗng thoát theo phương ngang đến PVD, lượng nước sau đó được dẫn lên trên mặt thoát nước theo lõi của PVD.…”

Section: Giới Thiệuunclassified

Phân tích ứng xử cố kết nền đất yếu gia cố PVD có xét đến sự giảm khả năng thoát nước phi tuyến theo chiều sâu

Phú¹

2020

TCKHCNXD

Nhiều nghiên cứu cho thấy rằng tốc độ cố kết nền đất yếu có gia cố bấc thấm (PVD) chịu ảnh hưởng trực tiếp tới khả năng thoát nước của PVD. Tuy nhiên, khả năng thoát nước của PVD (qw) thường giảm đáng kể theo độ sâu cắm bấc, điều này dẫn đến làm chậm quá trình cố kết trong nền. Bài báo này tiến hành phân tích cố kết thấm đối xứng trục của khối đất trụ tròn có gia cố PVD, trong đó qw được xem như giảm phi tuyến theo chiều sâu cắm PVD. Kết quả phân tích cho thấy rằng sự giảm phi tuyến theo chiều sâu của qw gây cản trở đáng kể cho quá trình cố kết của đất nền, và kết quả này thể hiện rõ hơn ở độ sâu lớn hơn trong nền đất yếu. Tuy nhiên, qw càng lớn thì sự ảnh hưởng này càng nhỏ. Lời giải giải tích được sử dụng phân tích các công trình thực tế với trường hợp chiều dày lớp đất yếu lớn, kết quả cho thấy rằng việc dự đoán ứng xử cố kết xét đến sự giảm phi tuyến của qw cho kết quả phù hợp với dữ liệu quan trắc tại hiện trường. Từ khóa: khả năng thoát nước; ứng xử cố kết; độ thấm của đất; nền gia cố bấc thấm; lời giải giải tích.

“…Norway's Drammen marine soft soil also has characteristics of marine soft soil, but Sangrey showed that the engineering properties of Drammen soft soil were different from those of Leda soft soil [2][3][4]. Other soft soils, such as London soft soil [5], Mexican soft soil [6], Japanese soft soil [7], Busan soft soil [8], Shenzhen soft soil, Shanghai soft soil and so on, all exhibit different marine soft soil characteristics [9][10][11][12][13][14][15][16]. The engineering characteristics of marine soft soil make the problem of consolidation and settlement of marine soft soil foundation complicated, but the one-dimensional consolidation theory by Terzaghi is not suitable for the analysis of complex marine soft soil foundation consolidation problems.…”

Section: Introductionmentioning

confidence: 99%

Improved Double-Layer Soil Consolidation Theory and Its Application in Marine Soft Soil Engineering

Chen

Luo

Liu

et al. 2019

JMSE

Marine soft soil foundation is a double-layer foundation structure with a crust layer and soft substratum. Moreover, it is common that there are various forms of drainage. Accordingly, based on Terzaghi’s consolidation theory and the continuous drainage boundary conditions theory of controllable drainage conditions, an improved double-layer soil consolidation theory considering continuous drainage boundary conditions was proposed. To improve the computational efficiency and accuracy, the Laplace transform and the Stehfest algorithm was used to deduce the numerical solution of the improved double-layer soil consolidation theory considering continuous drainage boundary conditions and to compile a computer program. Subsequently, the theory was validated and analyzed by the degenerated model of the perfectly permeable boundary conditions and the semi-permeable boundary conditions, respectively, which showed that this theory has higher accuracy. Simultaneously, the analysis of double-layer consolidation settlement under continuous drainage boundary conditions for marine soft soil foundation of Guangxi Binhai Highway was carried on. The result showed that the consolidation settlement calculated by the improved double-layer consolidation theory presented is basically consistent with the field measurement results, and that the correlation coefficient between them is higher. Accordingly, the research results can provide useful basic information for marine soft foundation engineering.