Experimental Research on the Change of Soft Soil’s Strength and Deformation Characteristics Caused by Dewatering

2012 ◽  
Vol 170-173 ◽  
pp. 679-682
Author(s):  
Hua Yuan ◽  
Jian Wei Zhang ◽  
Zhi Liang Zhao

Present research results have verified the significant soil reinforcement effect of dewatering. But the reinforcement effect of dewatering suffers ignorance in current excavation design process due to lack of systematic experimental study on the strengthening mechanism, causing a certain amount of waste. This paper first theoretically describes the relationship between the increase of soil shear strength and that of compression modulus owing to pumping, then investigates the influence of well-point pumping on Shanghai soil’s shear strength and deformation properties through indoor test. The results may provide useful suggestions for future excavation support design.

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Lianzhen Zhang ◽  
Qingsong Zhang ◽  
Zhipeng Li ◽  
Hongbo Wang

In fracture or compaction grouting projects of sand layer, there exist many compacted sand regions on both sides of grout veins or around grout bulbs. It has an important effect on the final reinforcement effect of the sand layer that how much performance of the sand layer is improved after being compacted. Compression modulus, cohesion, and permeability coefficient are selected to be the performance indexes of the compaction reinforcement effect of sand. The relationship between the performance properties of sand and grouting pressure has been tested and analyzed. And influences of clay content and initial water ratio of sand on the compaction reinforcement effect have been studied. Results show that compaction can effectively improve the mechanical properties and impermeability properties of sand. Compression modulus of sand increases by 2∼18 times. The cohesion of sand increases from the scope of 9.4∼26 kPa to the scope of 40∼113.6 kPa. The permeability coefficient of sand decreases from the scope of 1.0 × 10−2∼ 8.33 × 10−4 cm/s to the scope of 2.19 × 10−4∼2.77 × 10−9 cm/s. When the clay content of sand is smaller than about 20%, sand cannot be reinforced effectively by compaction. Cohesion cannot be improved significantly and the permeability coefficient cannot be reduced markedly. A high initial water ratio of sand is beneficial to improve the compression modulus of compacted sand and goes against the improvement of cohesion of compacted sand. In addition, the initial water ratio has little effect on the permeability coefficient of compacted sand. In the end, fitting formulas have been developed to quantitatively describe the compaction reinforcement effect of sand by different grouting pressures.


2011 ◽  
Vol 255-260 ◽  
pp. 4012-4016
Author(s):  
Jun Qing Ma ◽  
You Xi Wang

This paper studies relationship between soil-cement parameters and unconfined compressive strength. The research in tensile strength and deformation modulus of soil-cement is an important basis for soil-cement failure mechanism and intensity theory. They also impact cracks, deformation and durability of cement-soil structure. Shear strength and deformation of soil-cement is important to the destruction analysis and finite element calculations. Therefore it needs to study on tensile strength, shear strength and deformation modulus of soil-cement. Based on previous experiments, the relationship of tensile strength, shear strength, deformation modulus and unconfined compressive strength of soil-cement are quantitatively studied.


1972 ◽  
Vol 9 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Kaare Flaate

This study summarizes the information given in the literature as well as observations made by the author. The effects of driving piles on remolding, stresses, and properties of the clay are considered. It is concluded that timber piles cause strong remolding of a zone extending to 10–15 cm from the pile surface. Strength and deformation properties will undergo changes beyond this zone as well. Pile type, pile density, soil properties, and driving conditions influence the results. There seems to be very small changes in the average water content, since the reduction adjacent to the pile is counter-balanced by an increase between the piles. The undrained shear strength adjacent to the pile is in one case found to be much higher than the skin friction at failure.


Author(s):  
Nina TERREY ◽  
Sabine JUNGINGER

The relationship that exists between design, policies and governance is quite complex and presents academic researchers continuously with new opportunities to engage and explore aspects relevant to design management. Over the past years, we have witnessed how the earlier focus on developing policies for design has shifted to an interest in understanding the ways in which design contributes to policy-making and policy implementation. Research into policies for design has produced insights into how policy-making decisions can advance professional impact and opportunities for designers and the creative industries. This research looked into how design researchers and design practitioners themselves can benefit from specific policies that support design activities and create the space for emerging design processes.


2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhijun Zhou ◽  
Shanshan Zhu ◽  
Xiang Kong ◽  
Jiangtao Lei ◽  
Tong Liu

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.


2021 ◽  
Vol 239 ◽  
pp. 112282
Author(s):  
Ke-Jing Zhou ◽  
Wei-Jian Yi ◽  
Hui Chen ◽  
Yun Zhou ◽  
Wang-Xi Zhang

2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.


e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 103-110
Author(s):  
Anfu Guo ◽  
Hui Li ◽  
Jie Xu ◽  
Jianfeng Li ◽  
Fangyi Li

AbstractThe performance of Polystyrene microporous foaming (PS-MCF) materials is influenced by their microstructures. Therefore, it is essential for industrializing them to investigate the relationship between their microstructure and material properties. In this study, the relationship between the microstructure, compressive property, and thermal conductivity of the PS-MCF materials was studied systematically. The results show that the ideal foaming pressure of PS-MCF materials, obtaining compression performance, is around 20 MPa. In addition, the increase of temperature causes the decrease of sample density. It effects that the compression modulus and strength increase with the decrease of foaming temperature. Because the expansion rate and cell diameter of the PS-MCF materials reduce the thickness of cell wall, they are also negatively correlated with their mechanical properties. Moreover, there is a negative linear correlation between the thermal conductivity and cell rate, whereas the cell diameter is positively correlated with the thermal conductivity.


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