Consolidation Settlement Analyses on a Composite Foundation System Combined with Walled and Columniform Soil Improvement

2010 ◽  
Vol 163-167 ◽  
pp. 2318-2327
Author(s):  
Wei Li ◽  
Fei Gao ◽  
He Huang ◽  
Haruyuki Yamamoto ◽  
Kinji Takeuchi
Keyword(s):  
Environmental Influence ◽  
Soil Layer ◽  
Soil Improvement ◽  
Differential Settlement ◽  
Composite Foundation ◽  
Shallow Foundation ◽  
Hydraulic Pressure ◽  
Raft Foundation ◽  
Consolidation Settlement ◽  
Geological Situation

To satisfy the geotechnical strength requirements and the serviceability requirements, types of foundation systems (such as shallow foundation, pile foundation and composite foundation) have been developed. Of course, the type of foundation system is determined by many factors such as ground condition, economy and environmental influence of construction. To cope with weak or compressible soils, the authors present a raft foundation system with walled and columniform soil improvement for multistory buildings, which is economical and environment-friendly. In this raft foundation system, different columniform soil improvements in size and depth are used, and the subgrade under the edge of the foundation is walled by soil improvement. It can effectively control differential settlement and prevent relative rising of the structure by adjusting the size and depth of columniform soil improvements according to the soil layer difference of geological situation under the building. We have performed series numerical analyses under two-dimensional plane strain condition to study the settlement behaviors of the composite foundation system, and its effects on controlling differential settlement and improving bearing capacity were verified for immediate condition. As a continuous research, consolidation settlement analyses are performed, the process of excess hydraulic pressure dispersion with time and the consolidation settlement development are studied in this paper.

Settlement Analysis of Piled-Raft Foundation Using Numerical Method

2012 ◽  
Vol 204-208 ◽  
pp. 1276-1281 ◽  
Author(s):  
Wen Tsung Liu ◽  
Chun Yi Lin
Keyword(s):  
Soil Improvement ◽  
Soil Parameters ◽  
Soil Consolidation ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Initial Stage ◽  
Consolidation Settlement ◽  
The Impact ◽  
Settlement Analysis

The study gives an example of the sinking pier case at Takeda Interchange of National Highway NO.3 in Taiwan. We got the monitoring data, explored the impact on the consolidation settlement of piled-raft foundation from construction procedure and soil improvement by finite element method「Plaxis8.2」and predicted the degree of post-settlement. Analytic results are shown as follows：Firstly, the soil consolidation settlement model is built by the estimated soil parameters using the data of soil exploration. The calculation value of settlement and the measured value are identical. Secondly, soil improvement only shows effective in initial stage. The pre-consolidation settlement is smaller when building embankment is before pier than when building pier is before embankment.

Experimental Research on Settlement Distribution of Composite Foundation Configured with Walled Soil Improvement

2013 ◽  
Vol 748 ◽  
pp. 1109-1113
Author(s):  
Wei Li ◽  
De Min Wang ◽  
Chao Li ◽  
Qing Hui Zeng
Keyword(s):  
Bearing Capacity ◽  
Experimental Research ◽  
Soil Improvement ◽  
Differential Settlement ◽  
Composite Foundation ◽  
Geological Condition ◽  
The Poor ◽  
And Control ◽  
Settlement Distribution ◽  
Stiffness Distribution

Because of the poor geological condition in the soft area, the bearing capacity of the ground is lower, which will cause large settlement of buildings. To cope with weak or compressible soils and control the differential settlement, the authors present a composite foundation system with net walled soil improvement. In this paper, the settlement of the composite foundations configured with different forms of walled soil improvement is studied by model tests. Through these tests, we see that the settlement in the center is much larger than that at the edge under uniform ground rigidity, and foundations differential settlement or settlement distribution is mainly decided by the rigidity and stiffness distribution of ground. If increasing the depth or area of walled soil improvement near the center of foundation, the differential settlement can be greatly reduced.

Numerical Analysis on Interaction of Superstructure-Piled Raft Foundation-Foundation Soil

2011 ◽  
Vol 261-263 ◽  
pp. 1578-1583
Author(s):  
Yong Le Li ◽  
Jiang Feng Wang ◽  
Qian Wang ◽  
Kun Yang
Keyword(s):  
Design Method ◽  
Bending Moment ◽  
Load Sharing ◽  
Differential Settlement ◽  
Pile Head ◽  
Secondary Stress ◽  
Foundation Soil ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Soil Load

based on the finite element method of superstructure-the pile raft foundation-the foundation soil action and interaction are studied. Research shows that the common function is considered, fundamental overall settlement and differential settlement with the increase of floor of a nonlinear trend. The influence of superstructure form is bigger for raft stress, the upper structure existing in secondary stress, and the bending moment and axial force than conventional design method slants big; With the increase of the floors, pile load sharing ratio is reduced gradually,but soil load sharing ratio is increased. Along with the increase of the upper structure stiffness, the load focused on corner and side pile; Increasing thickness of raft, can reduce the certain differential settlement and foundation average settlement, thus reducing the upper structure of secondary stress and improving of foundation soil load sharing ratio, at the same time the distribution of counterforce on the pile head is more uneven under raft, thus requiring more uneven from raft stress, considering the piles under raft and the stress of soils to comprehensive determines a reasonable raft thickness, which makes the design safety economy. As the foundation soil modulus of deformation of foundation soil improvement, sharing the upper loads increases, counterforce on the pile head incline to average, raft maximum bending moment decrease gradually.

scholarly journals Closing Yield Gaps through Soil Improvement for Maize Production in Coastal Saline Soil

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 573 ◽  
Author(s):  
Jishi Zhang ◽  
Xilong Jiang ◽  
Yanfang Xue ◽  
Zongxin Li ◽  
Botao Yu ◽  
...  
Keyword(s):  
Crop Production ◽  
High Salinity ◽  
Saline Soil ◽  
Soil Layer ◽  
Soil Improvement ◽  
Salinity Level ◽  
Yield Potential ◽  
Coastal Saline Soil ◽  
Salinity Levels ◽  
Yield Gaps

As efforts to close crop production yield gaps increase, the need has emerged to identify cost-effective strategies to reduce yield losses through soil improvement. Maize (Zea mays L.) production in coastal saline soil is limited by high salinity and high pH, and a limited number of soil amendment options are available. We performed a field experiment in 2015 and 2016 to evaluate the ability of combined flue gas desulfurization gypsum and furfural residue application (CA) to reduce the maize yield gap and improve soil properties. We carried out the same amendment treatments (CA and no amendment as a control) under moderate (electrical conductivity (EC1:1) ≈ 4 dS m−1) and high (EC1:1 ≈ 6 dS m−1) salinity levels. Averaged over all salinity levels and years, maize yields increased from 32.6% of yield potential in the control to 44.2% with the CA treatments. Post-harvest CA treatment increased the calcium (Ca2+) and soil organic carbon (SOC) contents while decreasing the sodium (Na+) content and pH in the upper soil layer. Corresponding nitrogen, phosphorus, potassium, calcium, and magnesium accumulations in maize were significantly increased, and Na accumulation was decreased in the CA group compared with the control. The economic return associated with CA treatment increased by 215 $ ha−1 at the high salinity level compared with the control, but decreased at the moderate salinity level because of the minor increase in yield. The results of this study provide insight into the reduction of yield gaps by addressing soil constraints.

scholarly journals A method of calculating the bearing capacity of sand pile composite foundations in a mucky soil layer considering consolidation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yongtao Zhang ◽  
Yuqing Liu ◽  
Huiwu Luo ◽  
Peishuai Chen ◽  
Dejie Li ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Water Content ◽  
Effective Stress ◽  
Void Ratio ◽  
Soil Layer ◽  
Composite Foundation ◽  
Engineering Practice ◽  
Application Process ◽  
Sand Pile ◽  
Cavity Expansion Theory

AbstractIn engineering practice, the measured bearing capacity of a sand pile composite foundation in a mucky soil layer is much larger than the design value. Based on the sand pile construction and the load application process, a method of calculating the bearing capacity of the foundation based on the effective stress was proposed. Cavity diameter expansion in sand pile construction was simplified into a planar problem, and the cavity expansion theory was used to establish the expression of the rate of displacement and the horizontal stress increase. Based on the e–p curve and the calculation of the degree of consolidation, the relationships between the horizontal and vertical effective stress and the void ratio were obtained. According to the close relationship between the bearing capacity of the foundation in a mucky soil layer and the water content, an expression describing the relationships between the bearing capacity of the foundation, effective stress, void ratio, and water content was established. For the temporary engineering foundation treatment project, which needs a high bearing capacity but allows large foundation deformation, the design of sand pile composite foundations uses these relationships to take the consolidation effect of mucky soil into consideration, thereby reducing the replacement rate and lowering the construction cost.

The Influence of Pavement Construction on Embankment Settlement in Highway Extension Project

2013 ◽  
Vol 361-363 ◽  
pp. 1787-1793
Author(s):  
Xian Lin Wei ◽  
Yi Min Wang ◽  
Ze Min Zeng ◽  
Luo Zhang
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Composite Foundation ◽  
Standard Requirement ◽  
Construction Period ◽  
Small Influence ◽  
Load Carrying ◽  
Pavement Construction ◽  
Layer Deformation

In order to reduce the soft soil layer deformation due to pavement construction, equal preloading of pavement is usually adopted after embankment filling in soft ground region. But as the ground treatment effect of pile-supported and geosynthetic reinforced embankment is satisfactory with great load-carrying ability, the necessity of applying equal preload is worth discussing. Combined with the practice of Guangzhou-Sanshui expressway widening project, the settlements in surveying sections during the paving construction period in extension area were monitored. The monitoring data shows that pavement load had small influence on embankment settlement: the uneven settlement between newly widen and existing road is small and the post-construction settlements are controlled within the standard requirement. On the premise of guaranteeing the construction quality of composite-foundation and filling compaction degree, it is unnecessary to take equal preloading to avoid excessive embankment settlement caused by the pavement structure.

ANALYTICAL STUDY ON PILED-RAFT FOUNDATION CONSIDERING NONLINEAR BEHAVIOR OF GIBSON SOIL

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
He Huang ◽  
Haruyuki Yamamoto
Keyword(s):  
Analytical Study ◽  
Soil Layer ◽  
Nonlinear Behavior ◽  
Elastic Theory ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation

Randolph (1994) was proposed simplified estimated equations to carried out the proportion of load between the components of piled-raft foundation. These equations are based on elastic theory. Therefore, Authors focus on the point of applicability for nonlinear behavior of soil. This paper is a part of study on behavior of piled-raft foundation under considering the nonlinear behavior of ground. Authors already discussed the effect of nonlinear behavior of soil on the equations by Randolph. In addition, as the extension of research, authors also discussed the applicability of these equations for irregular raft shape. However, foundations were rarely set in an ideal homogeneous single soil layer in our previous studies. Therefore, the applicability of these equations are discussed in case of inhomogeneous soil (Gibson soil) in this paper.

Bearing Capacity Improvement of Shallow Foundations Using Cement-Stabilized Sand

2016 ◽  
Vol 723 ◽  
pp. 795-800 ◽  
Author(s):  
Habib Rasouli ◽  
Hana Takhtfirouzeh ◽  
Abbasali Taghavi Ghalesari ◽  
Roya Hemati
Keyword(s):  
Bearing Capacity ◽  
Soil Stabilization ◽  
Cement Content ◽  
Experimental Tests ◽  
Dry Weight ◽  
Soil Improvement ◽  
Reinforced Soil ◽  
Shallow Foundation ◽  
Engineering Properties ◽  
Suitable Material

In order to attain a satisfactory level of safety and stability in the construction of structures on weak soil, one of the best solutions can be soil improvement. The addition of a certain percentage of some materials to the soil may compensate for its deficiency. Cement is a suitable material to be used for stabilization and modification of a wide variety of soils. By using this material, the engineering properties of soil can be improved. In this study, the effect of soil stabilization with cement on the bearing capacity of a shallow foundation was studied by employing finite element method. The material properties were obtained by conducting experimental tests on cement-stabilized sand. Cement varying from 2% to 8% by soil dry weight was added for stabilization. The effect of reinforced soil block dimensions, foundation width and cement content were investigated. From the results, it can be figured out that by stabilizing the soil below the foundation to certain dimensions with the necessary cement content, the bearing capacity of the foundation will increase to an acceptable level.

scholarly journals Settlement Analysis of Sand Compaction Pile Composite Foundation in Transition Section of Immersed Tube Tunnel

2022 ◽  
Vol 2148 (1) ◽  
pp. 012031
Author(s):  
Jinfang Hou ◽  
Jian Yu
Keyword(s):  
Data Collection ◽  
Soft Soil ◽  
Composite Foundation ◽  
Wireless Transmission ◽  
Long Distance ◽  
Transition Section ◽  
Surcharge Preloading ◽  
Consolidation Settlement ◽  
Distance Data ◽  
Settlement Analysis

Abstract The foundation of the immersed tube transition section of the Hong Kong-Zhu Hai-Macao Bridge Project is distributed with thick silty soil. The method of sand compaction pile + surcharge preloading is used to treat the soft soil ground. In order to determine the foundation consolidation settlement and subsequent residual settlement in the transition section of the immersed tube tunnel, a monitoring system using long wires combined with wireless transmission and long-distance data collection was developed to obtain the measured foundation settlements during the surcharge period. After comparing the measured value with the calculated value, the formula for the composite foundation of the sand compaction pile was revised to obtain a more reasonable residual settlement of the foundation, which could guide the design and construction of the immersed tube tunnel.

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