Mechanism and Application on Extra-Long Sand Wells for Deep Soft Foundation Treatment in Highways

2011 ◽  
Vol 250-253 ◽  
pp. 3128-3133
Author(s):  
He Cheng Liang ◽  
Li Jia Chang ◽  
Ai Guo Zhou

The soft base in the testing section of Jiang-zhu highwaysis 55 meters deep, and its mechanical property is not better than that of silt soil, the sand-wick drained length is one of the crucial factors for this highwaywhich influences the consolidation speed. Based on the characteristic of soft foundation, experiences and the interrelationship between the processing area and the subjacent bed effecting on draining, the mechanism of extra-long sand-wick for the extra-deep soft foundation is studied. The theoretical consolidation degree in the deep soft foundation treating with extra-long sand-wick drain had been calculated, the designed depth of sand-wick drain were 25 and 22 meters. Moreover, the total settlement will be predicted. According to the monitoring data of displacement and settlement during loading, the characteristic of consolidation settlement of the soft soil foundation had been analyzed. The results indicated that the settlement was very sensitive to the loading speed. The sedimentation became fast with the increasing loading. The sedimentation speed was always very high, which was 15 to 25mm/day on the average. During the prophase of pre-compaction, the consolidation degree of section K53+242.47 (h=25m) was up to 80% in 350 days, which was much faster than the section K53+402.47 (h=22m). Moreover, the soft soil foundation was consolidated stably according to the strict dynamic monitoring data. By using hyperbolic theory to analyze monitoring data, the predictive settlement value of post-project can meet the designed requirement. The treating effect of the 25m depth sand-wick drain was better than that of 22m, which provided available data for extra thick soft foundation treatment.

2012 ◽  
Vol 204-208 ◽  
pp. 1622-1625 ◽  
Author(s):  
Zi Lin Li ◽  
Kai Feng Zhang

Foam lightweight soil is a new type of material appearing in recent years, whose advantages are paid more and more attention to by engineers and it will have broad application prospect in the engineering. An in-depth study application of foam lightweight soil in the complex of railway soft soil foundation treatment what based on a railway foundation project in Tianjin, this paper discusses the actual application state of foam lightweight soil in handling of special railway soft soil foundation. Through in-depth analysis of the advantages of a foam lightweight soil, optimization of construction replacement thickness and moisture density, discussion on construction of it, we can find large advantages of foam lightweight soil as replacement material in the complex railway soft soil foundation treatment, and provide new ideas about processing complex soft foundation.


2014 ◽  
Vol 919-921 ◽  
pp. 1184-1190
Author(s):  
Jie Yu ◽  
Tian Yue Chu ◽  
Quan Mei Gong

On the background of one railway freight yard in Xiao Yong railway , and firstly the use of thin-walled tubular pile is determined in railroad yard through the comparison with other methods in the soft foundation reinforcement. Secondly, the effect of the soft-soil foundation reinforcement combined with the numerical simulation and the measured data is analyzed. Finally, it is defined that the thin-walled tubular piles has good value in the treatment of the high-filling railway yard, and it also can provide a new method for the improvement of the soft subgrade in railway freight yard.


2012 ◽  
Vol 190-191 ◽  
pp. 1207-1213
Author(s):  
Qi Xia Liu ◽  
Yang Zhao

The application of vacuum preloading for soft foundation treatment in grain storage is introduced from its principle,design,construction and the inspections. Its obvious effect is proved by example. The east coast of China is the most developed economical area and major grain and oil manufacturers. Many grain and oil depots have been established. However, in the places where the depots located, soil is soft dirt with low strength grade, high compressibility, small permeability and high possibility of plastic flow, has increased difficulties of grain and oil depots foundation construction. Without enough knowledge of soft soil and lacking of proper foundation construction method and good technology, depots may slip due to foundation’s erosion, and big settlement. If the structure slips, equipments for aeration, dehumidifier, antivirus equipment cannot work well. Based on the statement above, reasonable and effective methods for soft soil foundation work is the key point for construction of high quality and high standard grain and oil depots. This paper mainly discussed when we do depots construction work on the soft soil foundation, exact calculation, construction method and result test of fasten method for the soft foundation under the vacuum circumstance of preloading.


Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2117
Author(s):  
Keke Li ◽  
Wenyuan Xu ◽  
Liang Yang

The deformation characteristics of a raised and widened old Chinese roadway on a soft soil foundation are investigated in this study via finite element numerical simulation. The rules of ground surface settlement, slope foot lateral displacement, and ground surface settlement evolution of the roadbed under three modes (one-time construction of an eight-lane expressway, widened four-lane expressway, and raised/widened four-lane expressway) are compared. The ground surface settlement process of the eight-lane road foundation, which is formed by first widening and then raising the road, is highly complex. The ground surface settlement curve under the old road foundation increases and then decreases. The lateral displacement of the slope foot also interacts with the widening and raising of the eight-lane roadbed foundation. The range of lateral displacement is 70.05, 42.58, 124.81, 104.54 mm. Fifteen years after construction, the total settlement of the raised and widened roadbed is much larger than that of the one built directly. The total settlement values at the center of the two roadbeds are 297.05 and 234.85 mm, respectively. This manuscript provides data support for the reconstruction and expansion of roads on soft soil foundations, for choosing appropriate construction methods to build roads, and for avoiding major road damage, which is of great significance to the construction of road infrastructure in the future.


2011 ◽  
Vol 90-93 ◽  
pp. 2096-2100
Author(s):  
Yun Mei Meng ◽  
Yun Cao

The problem of disposing the soft soil foundation will appear inevitably during the construction of modem high way. There are many ways to dispose the soft foundation. One of those is CFG pile technology. Take the CFG pile technology in the GuangWu Expressway for example, the influence factors of embankment settlement were discussed in detai by numerical analysis, some useful conclusions are obtained from the computational results.


2020 ◽  
Vol 165 ◽  
pp. 04002
Author(s):  
Xiuyong Ni

Municipal road and bridge engineering is an important part of the transportation road construction in the city. Its construction quality directly affects the transportation quality and driving safety of the whole municipal road traffic. Among them, the foundation engineering of municipal road and bridge engineering is the main construction link. In the current municipal road and bridge construction process, it is often affected by many factors, leading to the reduction of the construction quality of municipal road and bridge engineering, especially the construction treatment of soft soil foundation in the foundation engineering, which is the main factor directly affecting the construction quality of municipal road and bridge. This paper first introduces the definition and relevant characteristics of soft soil foundation in the construction of municipal road and bridge engineering, and expounds the influence of soft soil foundation on municipal road and bridge engineering, and then analyzes the application of soft soil foundation treatment technology combined with the basic treatment ideas of soft soil foundation in the construction of municipal road and bridge.


2010 ◽  
Vol 150-151 ◽  
pp. 484-492
Author(s):  
Hong Jun Liu ◽  
Wei Shan ◽  
Yan Qiu Yang ◽  
Chun Jiao Wang ◽  
Ying Guo ◽  
...  

In order to provide technical reference in soft soil foundation treatment for construction of high-grade highway in wetlands soft soil area,by collecting undisturbed soil samples in Qiqihaer-Fuyu section of Jiagedaqi-Beijing highway and using triaxial tests, direct shear test, compressed consolidation testing and other testing methods, a detailed laboratory test and study has been carried out on the soft soil engineering properties and the comparative study on physical and mechanical index, compressed consolidation properties, shearing strength and shearing strength index and so on of wetlands soft soil and other genesis soft soil has been carried out,the results showed that: wetlands soft soil is better than delta soft soil in basic physical and mechanical index; comparing shearing strength parameters of wetlands soft soil and lacustrine soft soil shows that: under smaller consolidation degree and the consolidation pressure, their cohesion decreased with the increase of consolidation degree;with the consolidation degree and the consolidation pressure become bigger, the cohesion of wetlands soft soil is higher than lacustrine soft soil, internal friction angle changed little; Comparing with marine soft soil, the primary consolidation coefficient of wetlands soft soil is bigger and the secondary consolidation coefficient is smaller, that shows the foundation of wetlands soft soil is easy to drainage and consolidation. The research results have guiding significances for treatment of wetland soft soil foundation.


2013 ◽  
Vol 353-356 ◽  
pp. 225-228
Author(s):  
Fang Ding He ◽  
Jin Ping Cui ◽  
Jun Sui ◽  
Yi Fan Yu

The foundation settlement of soft soil highway engineering is too large, resulting in pavement wave-like because of differential settlement between the structure and adjacent soft soil foundation, which seriously impacts on traffic safety. Considering the soft soil foundation in the foundation treatment methods of CFG pile, sand bag well, powder spraying pile, we analyze differential settlement on the degree of influence structure internal force distribution, then provide the reference for the design and calculation.


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