scholarly journals Soil carbon redistribution and organo-mineral associations after lateral soil movement and mixing in a first-order forest watershed

Geoderma ◽  
2018 ◽  
Vol 319 ◽  
pp. 142-155 ◽  
Author(s):  
Beth A. Fisher ◽  
Anthony K. Aufdenkampe ◽  
Kyungsoo Yoo ◽  
Rolf E. Aalto ◽  
Julia Marquard
Keyword(s):  
Soil Carbon ◽  
Soil Movement ◽  
First Order ◽  
Forest Watershed ◽  
Mineral Associations ◽  
Carbon Redistribution ◽  
Lateral Soil Movement

scholarly journals Model Tests on Single Piles Subjected to Lateral Soil Movement

1995 ◽  
Vol 35 (4) ◽  
pp. 85-92 ◽  
Author(s):  
H.G. Poulos ◽  
L.T. Chen ◽  
T.S. Hull
Keyword(s):  
Model Tests ◽  
Soil Movement ◽  
Single Piles ◽  
Lateral Soil Movement

scholarly journals Towards a representation of priming on soil carbon decomposition in the global land biosphere model ORCHIDEE (version 1.9.5.2)

2016 ◽  
Vol 9 (2) ◽  
pp. 841-855 ◽  
Author(s):  
Bertrand Guenet ◽  
Fernando Esteban Moyano ◽  
Philippe Peylin ◽  
Philippe Ciais ◽  
Ivan A Janssens
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Carbon ◽  
Global Scale ◽  
Soil Incubation ◽  
First Order ◽  
Carbon Decomposition ◽  
Litter Manipulation ◽  
Global Land ◽  
Biosphere Model

Abstract. Priming of soil carbon decomposition encompasses different processes through which the decomposition of native (already present) soil organic matter is amplified through the addition of new organic matter, with new inputs typically being more labile than the native soil organic matter. Evidence for priming comes from laboratory and field experiments, but to date there is no estimate of its impact at global scale and under the current anthropogenic perturbation of the carbon cycle. Current soil carbon decomposition models do not include priming mechanisms, thereby introducing uncertainty when extrapolating short-term local observations to ecosystem and regional to global scale. In this study we present a simple conceptual model of decomposition priming, called PRIM, able to reproduce laboratory (incubation) and field (litter manipulation) priming experiments. Parameters for this model were first optimized against data from 20 soil incubation experiments using a Bayesian framework. The optimized parameter values were evaluated against another set of soil incubation data independent from the ones used for calibration and the PRIM model reproduced the soil incubations data better than the original, CENTURY-type soil decomposition model, whose decomposition equations are based only on first-order kinetics. We then compared the PRIM model and the standard first-order decay model incorporated into the global land biosphere model ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems). A test of both models was performed at ecosystem scale using litter manipulation experiments from five sites. Although both versions were equally able to reproduce observed decay rates of litter, only ORCHIDEE–PRIM could simulate the observed priming (R2  =  0.54) in cases where litter was added or removed. This result suggests that a conceptually simple and numerically tractable representation of priming adapted to global models is able to capture the sign and magnitude of the priming of litter and soil organic matter.

scholarly journals Review on Lateral Stability of Piled Riverine Structures in the Estuaries of Sarawak

2018 ◽  
Vol 7 (3.18) ◽  
pp. 21
Author(s):  
Lee Lin Jye ◽  
Shenbaga R. Kaniraj ◽  
Siti Noor Linda bt Taib ◽  
Fauzan Bin Sahdi
Keyword(s):  
Soft Soil ◽  
Natural State ◽  
Soil Conditions ◽  
Silty Clay ◽  
River Bank ◽  
Soil Movement ◽  
Geotechnical Problem ◽  
Construction Activity ◽  
Lateral Soil Movement ◽  
The Stability

Soft soil conditions with very soft and deep silty clay have constantly endangered the stability of the riverine and estuarine structures in Sarawak. There have been many failures of jetties, wharves and bridges in Sarawak. In many cases of failures, the piles were not designed to resist the lateral movement, unless they were included to stabilize unstable slopes or potential landslides. This practice may be due to reasons such as erroneously judging the river bank as stable in slope stability analysis or simply due to the inexperience of designers. Also, when the river bank approaches the limiting stability in its natural state any construction activity on the river bank could result in lateral soil movement. This paper highlights this important geotechnical problem in Sarawak. Then it presents the details of a few failures of estuarine structures. A review of situations causing lateral loading of piles is then presented. The results of the in-soil and in-pile displacement measurements are shown in this paper and it is found that the computation made to compare between field and 3D modeling is agreeable.  

scholarly journals Thrust and bending moment of rigid piles subjected to moving soil

2010 ◽  
Vol 47 (2) ◽  
pp. 180-196 ◽  
Author(s):  
Wei Dong Guo ◽  
H. Y. Qin
Keyword(s):  
Current Model ◽  
Bending Moment ◽  
Soil Movement ◽  
Model Pile ◽  
Experimental Apparatus ◽  
Lateral Soil Movement ◽  
Laterally Loaded ◽  
The Given ◽  
Maximum Thrust

An experimental apparatus was developed to investigate the behaviour of vertically loaded free-head piles in sand undergoing lateral soil movement (wf). A large number of tests have been conducted to date. Presented here are 14 typical model pile tests concerning two diameters, two vertical pile loading levels, and varying sliding depths with the movement wf driven by a triangular loading block. Results are provided for driving force as well as for induced shear force (T), bending moment (M), and deflection ( y) along the piles with wf / normalized sliding depth. The tests enable simple expressions to be proposed, drawn from the theory for a laterally loaded pile. The new expressions well capture the evolution of M, T, and y with soil movement observed in current model tests, and the three to five times difference in maximum bending moment (Mmax) from the two modes of loading. They further offer a good estimate of Mmax for eight in situ pile tests and one centrifuge test pile. The study quantifies the sliding resistance offered by a pile for the given wf profiles, pile location (relative to the boundary), and vertical load. It establishes the linear correlation between the maximum thrust (resistance T) and Mmax, regardless of the magnitudes of wf.

Measured Soil-Pile Interaction for Small Diameter Piles Embedded in Granular Soil Subjected to Lateral Soil Movement

2012 ◽  
Author(s):  
Muhannad T. Suleiman ◽  
Anne Raich ◽  
Lusu Ni ◽  
William Kingston ◽  
Timothy W. Polson ◽  
...  
Keyword(s):  
Small Diameter ◽  
Granular Soil ◽  
Soil Movement ◽  
Pile Interaction ◽  
Lateral Soil Movement

Effect of consolidation on responses of a single pile subjected to lateral soil movement

2015 ◽  
Vol 52 (6) ◽  
pp. 769-782 ◽  
Author(s):  
L.Z. Wang ◽  
K.X. Chen ◽  
Y. Hong ◽  
C.W.W. Ng
Keyword(s):  
Soft Clay ◽  
Bending Moment ◽  
Coefficient Of Consolidation ◽  
Construction Period ◽  
Soil Movement ◽  
Centrifuge Tests ◽  
Short Period ◽  
Lateral Soil Movement ◽  
Pile Response ◽  
Pile Length

Given extensive research carried out to study pile response subjected to lateral soil movement in clay, the effect of consolidation on the pile–soil interaction is rarely considered and systematically investigated. For this reason, four centrifuge tests were conducted to simulate construction of embankment adjacent to existing single piles in soft clay, considering two typical drainage conditions (i.e., drained and undrained conditions) and two typical pile lengths (i.e., relatively long pile and short pile). The centrifuge tests were then back-analyzed by three-dimensional coupled-consolidation finite element analyses. Based on reasonable agreements between the two, numerical parametric studies were conducted to systematically investigate and quantify the influence of construction rate and pile length on pile response. It is revealed that by varying drainage conditions, the piles respond distinctively. When the embankment is completed within a relatively short period (cvt/d2 < 2, where cv, t, and d denote the coefficient of consolidation, construction period, and pile diameter, respectively), the pile located adjacent to it deforms laterally away from the embankment. Induced lateral pile deflection (δ) and bending moment reduce with construction period. On the contrary, embankment constructed within a relatively long period (cvt/d2 > 200) leads the pile to deform laterally towards the embankment, with δ and bending moment increases with construction period. By halving the length of pile embedded in the drained ground, the maximum induced bending moment (BMmax) was slightly reduced (by 23%). On the other hand, shortening the length of the pile in the undrained ground is much more effective in reducing BMmax, i.e., halving pile length resulting in 78% reduction in bending moment. A new calculation chart, which takes various drainage conditions and pile lengths into account, was developed for estimation of BMmax.

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