Calculation of Land Subsidence Induced by Dewatering of Pit Based on Comprehensive Template Model

2012 ◽  
Vol 256-259 ◽  
pp. 187-192
Author(s):  
Duan Mei Zhang ◽  
Qin Wei Li ◽  
Run Chu Wei
Keyword(s):  
Elasticity Theory ◽  
Lower Limit ◽  
Land Subsidence ◽  
Deformation Modulus ◽  
Compression Modulus ◽  
Summation Method ◽  
Template Model ◽  
Unit Thickness ◽  
Lower Limits ◽  
Different Soils

Based on the hierarchical summation method of elasticity theory, the comprehensive template model of land subsidence induced by dewatering of pit is put forward. According to the soils experience range of conversion relationship β (between deformation modulus E0 and compression modulus Es ), we can calculate upper and lower limits of Es. When the compression modulus Es is respectively taken upper and lower limit, the curve between falling groundwater values and sedimentation values can be taken in conditions of unit thickness different soils of different pore ratio. So the comprehensive template model is built. The example shows that the comprehensive template model can be effectively calculated land subsidence induced by dewatering of pit.

scholarly journals Numerical and Theoretical Study on the Settlement of Capped Piles Composite Foundation under Embankment

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ming-Quan Liu ◽  
Da Huang ◽  
Yi-Xiang Song ◽  
Duo-Feng Cen
Keyword(s):  
High Speed ◽  
Soft Soil ◽  
Deformation Modulus ◽  
Compression Modulus ◽  
Calculation Model ◽  
Summation Method ◽  
Load Test ◽  
Composite Foundation ◽  
Static Load Test ◽  
Finite Element Software

Capped piles are efficient in settlement control and have been widely used in the reinforcement of soft soil foundations for high-speed railways and highways. In this study, scenarios involving both capped piles and ordinary piles without caps are numerically studied using the finite element software (ABAQUS). The settlement characteristics of capped piles composite foundation considering the effects of both the pile spacing and the ratio of pile cap to pile diameter are achieved. Based on the numerical results, assuming that the capped pile and the soil under the cap jointly bear load and settle together, a settlement calculation model for capped piles composite foundation is established. By both replacing the compression modulus with the deformation modulus obtained from the field static load test and calculating the area replacement ratio, the formula for calculating the total settlement of the capped piles composite foundation is derived using the layer-wise summation method. In addition, a real embankment engineering with capped piles composite foundation is adopted to validate the accuracy of this method; by comparing with other methods, the results show that this method is in better agreement with the field monitoring data. Therefore, the proposed method is recommended in the relevant engineering design.

scholarly journals Optimization Analysis of Settlement Parameters for Postgrouting Piles in Loess Area of Shaanxi, China

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhijun Zhou ◽  
Shanshan Zhu ◽  
Xiang Kong ◽  
Jiangtao Lei ◽  
Tong Liu
Keyword(s):  
Compression Modulus ◽  
Summation Method ◽  
Cone Penetration ◽  
Optimization Analysis ◽  
Loess Area ◽  
Elastic Compression ◽  
Settlement Calculation ◽  
Side Resistance ◽  
Load Tests ◽  
The Relationship

The settlement calculation of postgrouting piles is complex and depends on the calculation method and parameters. Static load tests were conducted to compare the settlement characteristics of nongrouting and postgrouting piles, and three vital parameters in the layer-wise summation method were revised to predict the settlement of postgrouting piles. The elastic compression coefficient was deduced based on the Mindlin–Geddes method by considering the influence of the change in the pile side resistance distribution and end resistance ratio on the elastic compression after grouting. The relationship between the compression modulus and soil gravity stress and cone penetration resistance were established, respectively, using experimental data. The optimum value of the settlement empirical coefficient was determined using regional data. Finally, we used the postgrouting pile of the Wuqi–Dingbian expressway as a practical example. The results obtained from the layer-wise summation method after parametric optimization were close to the measured values. The results of this study provide reference data and guidance for the settlement calculation of postgrouting piles in this area.

Model Tests on Additional Stress Transmission between Different Granular Materials in Foundation Soils

2014 ◽  
Vol 919-921 ◽  
pp. 828-834
Author(s):  
Chang Dan Wang ◽  
Shun Hua Zhou ◽  
Hui Su
Keyword(s):  
Granular Materials ◽  
Boundary Surface ◽  
Vertical Direction ◽  
Stress Transfer ◽  
Fine Sand ◽  
Compression Modulus ◽  
Model Tests ◽  
Additional Stress ◽  
Stress Transmission ◽  
Different Soils

To research and analyze the additional stress distribution and change of granular materials, the model tests are used to observe vertical additional stress in different position and depth in different foundations. And the comparison between observed values both in different soils and single soils is conducted to analyze the transmission and attenuation of additional stress in granular materials. The research results show that the existing of boundary surface can lead to different vertical additional stress transmit obviously. And with the increasing of loading, the vertical additional stress differences between that of different soils get larger, meanwhile, the ratio of stress differences to smaller additional stress increases slightly. With the increasing of depth, the attenuation rate of vertical additional stress of silty soil changes much fast than that of fine sand. Wherever in horizontal direction or vertical direction, the vertical additional stress of fine sand which has higher compression modulus in different soils is slightly larger than that in single soil and transfers additional stress (loading) more under the same loading. To granular materials, inner friction structure effect is evident influence to additional stress transfer.

scholarly journals Determining the lower limits of irrigation capacity use

2002 ◽  
Vol 47 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Petar Gogic
Keyword(s):  
Lower Limit ◽  
Irrigation System ◽  
Economic Effects ◽  
Cost Price ◽  
System Capacity ◽  
Production Structure ◽  
Economic Justification ◽  
System Use ◽  
Lower Limits

The objective of the study was to determine the limits of economic justification for irrigation system capacity use. The first step was focused on determining the lower limit of capacity use by comparing the economic effects of irrigation with the costs of the irrigation system use. In addition, while determining these limits the need was stressed to consider the economic effects of irrigation by optimizing the production structure and the modes for limit determination under irrigation and non-irrigation conditions. Eventually, the empirically verified possibility stating that this limit may be determined by comparing the water processing prices with its cost price is given. The limit was found to be the point at which these two prices equalize.

scholarly journals Settlement Computation of Homogeneous Base

2020 ◽  
Vol 23 (6) ◽  
pp. 90-98
Author(s):  
E. G. Pakhomova ◽  
O. I. Kutsenko ◽  
A. S. Morozova ◽  
A. R. Timokhina
Keyword(s):  
Critical Analysis ◽  
Soil Layer ◽  
Deformation Modulus ◽  
Summation Method ◽  
Layer By Layer ◽  
Average Pressure ◽  
Underground Structures ◽  
Regulatory Documents ◽  
Foundation Base ◽  
Sufficient Degree

Purpose of reseach. This article proposes the development of a new methodology for determining the settlement of a homogeneous foundation base on the basis of the layer-by-layer summation method, which reduces the amount of calculations performed.Methods. The boundary of the compressible stratum can be determined graphically from the condition that the additional stresses are equal to half the natural stresses. Knowing the value of the depth of the compressible stratum, we can determine the total value of the coefficients included in the well-known formula for calculating the settlement of the base by the method of layer-by-layer summation. Having determined the value of the specified coefficient in the layer located directly below the base of the foundation, we introduce the coefficient Kα, which reflects the proportion of sediment in the layer under consideration.Results. The application of the developed coefficient Kα allows determining the base settlement by calculating the deformations of one soil layer located directly below the base of the foundation, which greatly simplifies the design of underground structures. As an example, we consider a foundation, the average pressure under the sole of which is 1200 kPa, the laying depth d = 2 m, the base is homogeneous with a deformation modulus of 20 MPa and a specific gravity of γ = 18 kN / m3. The settlement of the building-basement system was calculated by the method of layer-bylayer summation and the critical analysis of the results was performed. When calculating precipitation by the method of layer-by-layer summation according to the known formulas given in SP 22.13330. 2016 “Foundations of buildings and structures”, it was obtained a draft value of 9 cm. When calculating the base deformations according to the proposed method, the boundary of the compressible thickness Hc = 5.7 m was graphically determined. The coefficient value was 0.203, and the draft was 9 cm.Conclusion. The settlement values determined in accordance with current regulatory documents and the developed methodology are the same, which allows us to conclude that the proposed method has a sufficient degree of reliability and can significantly facilitate the process of determining the deformations of the base of buildings and structures.

Lower limit of available water for three plant species grown on a medium-textured soil in southwestern Saskatchewan

1991 ◽  
Vol 71 (2) ◽  
pp. 247-252 ◽  
Author(s):  
H. W. Cutforth ◽  
P. G. Jefferson ◽  
C. A. Campbell
Keyword(s):  
Key Words ◽  
Lower Limit ◽  
Plant Species ◽  
Spring Wheat ◽  
Soil Factors ◽  
Available Water ◽  
Water Potentials ◽  
Lower Limits ◽  
Water Contents

Numerous researchers estimate and report laboratory-determined lower limit of available water contents using −1.5 MPa water potentials. For medium-textured soils, laboratory-measured lower limits should be determined at potentials of at least −4 MPa, and possibly −10 MPa, when using pressure membrane procedures. However, because the lower limit of available water is dependent upon environmental, plant and soil factors, we agree with Ratliff et al. (1983) that field-measured lower limits are preferable to laboratory-measured lower limits. Field-measured lower limits of available water did not vary markedly between spring wheat, alfalfa and grass. Key words: Lower limit of available water, wheat, alfalfa, grass

Selective filtering of light by coniferous forests and minimum light energy requirements for regeneration

1970 ◽  
Vol 48 (12) ◽  
pp. 2163-2167 ◽  
Author(s):  
Thomas Atzet ◽  
R. H. Waring
Keyword(s):  
Lower Limit ◽  
Forest Canopy ◽  
Coniferous Forest ◽  
Light Energy ◽  
Coniferous Forests ◽  
Minimum Light ◽  
Spectral Bands ◽  
Minimum Requirements ◽  
Lower Limits ◽  
Nm Range

Spectroradiometric analyses were made to examine the light-filtering capacity of coniferous forests and to establish the lower limits of light energy for growth of Pseudotsuga menziesii (Mirb.) Franco, Abies concolor (Gord. and Glend.) Lindl., and Pinns ponderosa Dougl. Light energy (400–750 nm) was recorded periodically on clear days in June and July at 48 points under four mixed conifer stands and segregated into four spectral bands (blue, 400–450; green, 500–550; red, 650–700; far-red, 700–750 nm). Minor changes in the proportion of light in one band to that in another occur throughout the day, but in general the 400- to 700-nm range appears rather uniformly absorbed by a coniferous forest canopy. Averaged for an entire day, only the far-red band showed a significant proportional increase under a coniferous canopy compared to unfiltered sunlight.The relation between the energy received in each of the spectral bands and the total recorded in the 400- to 700-nm range was linear. The sampled canopies transmitted up to 25% of full sunlight. Beneath the canopies, the ratio of blue to total energy (400–700 nm) was 0.1540. Green, red, and far-red had ratios of 0.1853, 0.1220, and 0.1207.Terminal growth of 34 seedlings was measured at the light-sampling points to provide a means of establishing lower limits of light energy for survival. The lower limit for Abies and Pseudotsuga was 1.85 langleys (ly) per day (400–700 nm). Pinus grew only where the light energy exceeded 36.8 ly/day.An interaction with moisture appears to influence the minimum requirements for light energy of a species. Where moisture was adequate throughout the growing season, the lower limit of light for Pseudotsuga seedling establishment was 1.85 ly/day; where moisture became limiting, the minimum light requirement increased to 6.64 ly/day.

scholarly journals THE EXISTENCE OF AN OLD QUASAR AT z=3.91 AND ITS IMPLICATIONS FOR Λ(t) DEFLATIONARY COSMOLOGIES

2004 ◽  
Vol 13 (07) ◽  
pp. 1321-1325 ◽  
Author(s):  
JOÃO VITAL CUNHA ◽  
ROSE CLÍVIA SANTOS
Keyword(s):  
Dark Matter ◽  
Energy Density ◽  
Total Energy ◽  
Lower Limit ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Observational Constraints ◽  
Total Energy Density ◽  
Lower Limits

We investigate some observational constraints on decaying vacuum cosmologies based on the recently discovered old high redshift quasar APM 08279+5255. This object is located at z=3.91 and has an estimated age of 2–3 Gyr. The class of Λ(t) cosmologies is characterized by a positive β parameter smaller than unity which quantifies the ratio between the vacuum and the total energy density. Assuming the lower limit age (2 Gyr) and that the cold dark matter contributes with Ω M =0.2 we show that β is constrained to be ≥0.07 while for an age of 3 Gyr and Ω M =0.4 the β parameter must be greater than 0.32. Our analysis includes closed, flat and hyperbolic scenarios, and it strongly suggests that there is no age crisis for this kind of Λ(t) cosmologies. Lower limits to the redshift quasar formation are also briefly discussed to the flat case. For Ω M =0.4 we found that the redshift formation is constrained by zf≥8.0.

scholarly journals Adaptation of ELISA Detection of Plasmodium Falciparum and Plasmodium Vivax Circumsporozoite Proteins in Mosquitoes to a Multiplex Bead-Based Immunoassay

2021 ◽  
Author(s):  
Alice Sutcliffe ◽  
Seth R. Irish ◽  
Eric Rogier ◽  
Micaela Finney ◽  
Sarah Zohdy ◽  
...  
Keyword(s):  
Lower Limit ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Limits Of Detection ◽  
Detection Range ◽  
Cutoff Value ◽  
Sporozoite Rate ◽  
The Impact ◽  
Lower Limits ◽  
Multiplex Bead

Abstract Background: Plasmodium spp. sporozoite rates in mosquitoes are used to better understand malaria transmission intensity, the relative importance of vector species and the impact of interventions. These rates are typically estimated using an enzyme-linked immunosorbent assay (ELISA) utilizing antibodies against the circumsporozoite protein of P. falciparum (Pf), P. vivax VK210 (Pv210) or P. vivax VK247 (Pv247), employing assays that were developed over three decades ago. The ELISA method requires a separate assay plate for each analyte tested and can be time consuming as well as requiring sample volumes not always available. The bead-based multiplex platform allows simultaneous measurement of multiple analytes and may improve the lower limit of detection for sporozoites.Methods: Recombinant positive controls for Pf, Pv210 and Pv247 and previously developed circumsporozoite (cs) ELISA antibodies were used to optimize conditions for the circumsporozoite multiplex bead assay (csMBA) and to determine the detection range of the csMBA. After optimizing assay conditions, known amounts of sporozoites were used to determine the lower limit of detection for the csELISA and csMBA and alternate cutoff measures were applied to demonstrate how cutoff criteria can impact lower limits of detection. Sporozoite rates from 1275 mosquitoes collected in Madagascar and 255 mosquitoes collected in Guinea were estimated and compared using the established csELISA and newly optimized csMBA. All mosquitoes were tested (initial test), and those that were positive were retested (retest). When sufficient sample volume remained, an aliquot of homogenate was boiled and retested (boiled retest), to denature any heat-unstable cross-reactive proteins. Results: Following optimization of the csMBA, the lower limit of detection was 25 sporozoites per mosquito equivalent for Pf, Pv and Pv247 whereas the lower limits of detection for csELISA were found to be 1400 sporozoites for Pf, 425 for Pv210 and 1650 for Pv247. Combined sporozoite rates after re-testing of samples that initially tested positive for Madagascar mosquitoes by csELISA and csMBA were 1.4% and 10.3%, respectively, and for Guinea mosquitoes 2% by both assays. Boiling of samples followed by csMBA resulted in a decreased in the Madagascar sporozoite rate to 2.8-4.4% while the Guinea csMBA sporozoite rate remained at 2.0%. Using an alternative csMBA cutoff value of median fluorescence intensity (MFI) of 100 yielded a sporozoite rate after confirmational testing of 3.7% for Madagascar samples and 2.0% for Guinea samples. Whether using csMBA or csELISA, the following steps may help minimize false positives: specimens are appropriately stored and bisected anterior to the thorax-abdomen junction, aliquots of homogenate are boiled and retested following initial testing, and an appropriate cutoff value is determined.Conclusions: The csMBA is a cost-comparable and time saving alternative to the csELISA and may help eliminate false negatives due to a lower limit of detection, thus increasing sensitivity over the csELISA. The csMBA expands the potential analyses that can be done with a small volume of sample by allowing multiplex testing where analytes in addition to Pf, Pv210 and Pv247 can be added following optimization.

URINARY GONADOTROPHIN EXCRETION IN HYPOGONADAL MEN

1965 ◽  
Vol 32 (2) ◽  
pp. 237-243 ◽  
Author(s):  
J. S. M. HUTCHINSON ◽  
J. M. WORDEN ◽  
F. T. G. PRUNTY
Keyword(s):  
Lower Limit ◽  
Extraction Method ◽  
Klinefelter Syndrome ◽  
Seminiferous Tubules ◽  
Syndrome Type ◽  
Normal Range ◽  
Mouse Uterus ◽  
Clear Cut ◽  
Lower Limits ◽  
Testicular Disease

SUMMARY Gonadotrophin excretion in 50 hypogonadal males has been investigated by the kaolin-acetone extraction method and the mouse uterus test. Patients with panhypopituitarism had values for gonadotrophin excretion below the normal range while those thought to have gonadotrophin insufficiency not due to hypopituitarism had values either below or around the lower limit of the normal range. Patients with primary testicular failure, involving both seminiferous tubules and interstitial cells, including those of the Klinefelter syndrome type, usually had a high gonadotrophin excretion. Patients with failure of the seminiferous tubules had values within the normal range only. In patients with gynaecomastia without evidence of testicular disease, gonadotrophin excretion was usually normal. The differentiation of abnormal levels, particularly at the lower limits, was not always clear-cut.

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