岩土工程技术

Monitoring and Analysis on One Deep Foundation Pit Used SMW Pile Enclosure Structure

Lin Lixiang

2013, 27(3): 109-114. doi: 10.3969/j.issn.1007-2993.2013.03.001

[Abstract](63) [PDF 4201KB](8)

Abstract:
Introduced monitoring process of deep foundation pit by SMW pile enclosure structure in Shanghai,and combined with the design and construction technology of retaining structure and the surrounding environment of the deformation are analyzed.Including deep horizontal displacement of the enclosure structure,axial force,uplift and settlement of column in pit,changes about waters out of pit,characteristic of settlement about buildings.The results showed that:adopting reasonable technology of construction according to the design scheme can effectively control the deformation of the retaining structure and the surrounding environment in the smaller range of values,for the soft soil region using SMW pile for Deep Foundation Pit enclosure structure design corresponding accumulation of experience for the similar parameters,construction of deep foundation pit excavation technology provides a reasonable choice reference.

Analysis and Application of Double Annular Supporting in Irregular Deep Foundation Pit

Wang Tao

2013, 27(3): 115-117,121. doi: 10.3969/j.issn.1007-2993.2013.03.002

[Abstract](49) [PDF 1619KB](10)

Abstract:
Based on engineering example,this article is carried out on characteristics and stress mechanism of double annular supporting system.Differences between monitoring actual value and design value are discussed.Problems about design and constructions process that should be paid attention to are analyzed.A suitable enclosure method for irregular deep foundation pit is provided.

Experimental Research on Compression Deformation Characteristics of Bulky Rock Material

Liu Youjun, Hou Xijiao, Wu Yong

2013, 27(3): 118-121. doi: 10.3969/j.issn.1007-2993.2013.03.003

[Abstract](25) [PDF 784KB](5)

Abstract:
Compression deformation tests of bulky rock material that in saturation conditions and natural conditions were carried out.In order to provide the reliable theory basis for engineering practices,the compression deformation mechanism and rules of bulky rock material was discussed,the results showed that:1) compression characteristics of bulky rock material is performance of the low compressibility,the compression deformation is given priority to plastic deformation and also performance of the instantaneous deformation; 2) compression modulus in saturation conditions is obviously less than the one in natural conditions,so bulky rock material produce large deformation in saturation condition;3) the pressure characteristic value of compression deformation is 400kPa,when the pressure is greater than this value the compression modulus is lower,and the deformation is increase,void ratio is also reduced obviously; 4) the rock softening action intensifies bulky rock material compression deformation.

Discussion on Related Problems of Large Diameter-Pile in Complex Rock Foundation Area

Xu Siyi, Peng Manhua, Zhang Haishun

2013, 27(3): 122-125. doi: 10.3969/j.issn.1007-2993.2013.03.004

[Abstract](31) [PDF 1423KB](6)

Abstract:
The selection of pile foundation scheme,calculation of rock-socket depth and shear-resistance,depth correction of foundation bearing capacity in complex rock area are discussed in this paper.

A Method for Coefficient of Subgrade Reaction of CFG Pile Composite Subgrade Under Different Arrangement

Li Jianguang, Liu Huancun, Wang Zuping

2013, 27(3): 126-130,136. doi: 10.3969/j.issn.1007-2993.2013.03.005

[Abstract](45) [PDF 1300KB](8)

Abstract:
Mindlin Formula and Boussinesq Formula are applied to the compute settlement of CFG composite subgrade,the coefficient of subgrade reaction computed from the above settlement is similar to that computed from the settlement survey.The compute method of coefficient of subgrade reaction in this paper is proved to be practicable.

Sustainable Management of Geothermal Resources

Liu Sida, Wang Shufang, Liu Jiurong

2013, 27(3): 131-136. doi: 10.3969/j.issn.1007-2993.2013.03.006

[Abstract](37) [PDF 1694KB](4)

Abstract:
Geothermal is a kind of clean energy source,and is also renewable in most cases.Although geothermal development may bring out important social,economical and environmental effects,it is also possible to have noticeable impact on the environment.Therefore,it is essential to have proper management to the geothermal systems under exploitation.According to the principle of sustainable development,the definition for the allowable production from a geothermal system may be stated as the constant and maximum amount of energy can be exploited under the condition that the reservoir pressure is properly controlled,and without causing serious environmental problem.If the production from a geothermal system is not more than its allowable production,it can be referred as sustainable exploitation; otherwise it is called excessive exploitation.To ensure the sustainability of a geothermal system,it is important to set up and update the reservoir model of the geothermal system,to have a proper monitoring program,and to carry out reinjection.

Study on the Characteristics and Countermeasures of Ganhe Gully Debris Flow in Shifang,Sichuan

Zhao Zhiwei, Li Baoqiang

2013, 27(3): 137-140. doi: 10.3969/j.issn.1007-2993.2013.03.007

[Abstract](57) [PDF 1206KB](6)

Abstract:
Ganhe gully which is an old debris flow gully had broken out on August,1996.The disaster destroyed the Red light bridge and lumber mill at the gully mouth.According to the investigation on the debris flows, it is found that the gully has rich matter-source which are concentrated in 3# gully region after 5.12 Wenchuan earthquake.The main kind of matter-source are rock fall and landslide, the dynamic reserves is about 260 000 m³.The debris flow is defined as large-scale with 20 000 m³ solid matter bursting out.Combining with the construction characteristics of Ganhe debris flow gully,this paper proposes related controlling measures and suggestions.

Design and Research of Anti-Float Anchor in Soil

Lin Zhongwei, Liu Xinyi, Lin Daming

2013, 27(3): 141-146. doi: 10.3969/j.issn.1007-2993.2013.03.008

[Abstract](54) [PDF 3151KB](12)

Abstract:
The development and utilization of underground space makes underground building became a very important part in the engineering. Underground space and is closely related to the condition of geotechnical engineering, and the direct interaction of the condition raises related questions. Anti-floating of underground construction is one of the most important security issues. Different companies use different methods of anti-floating in different regions. For many years, after the study of geotechnical engineering practice, anti-float anchor became an important way for underground construction of anti-floating. The design and construction of anti-float anchor are practiced in a lot of ways. The design and practical effect of anti-float anchor in soil are studied in Beijing. The construction technology of continuous flight auger drilling and post-inserting main reinforcement is promoted and practiced, and the results are summarized to guide the same engineering practices.

Simple Analysis of Energy Pile Ground-source Heat Pump System

Li Chunbao

2013, 27(3): 147-149,157. doi: 10.3969/j.issn.1007-2993.2013.03.009

[Abstract](26) [PDF 3049KB](4)

Abstract:
Ground-source heat pump air conditioning system is technique using shallow geothermal energy for heating and cooling. Energy pile ground-source heat pump system is one of ground-source heat pump air conditioning system.This article simply analyses the characteristic of energy pile ground-source heat pump system. Although it has understanding advantages, in view of its little use,it need to be deeply researched and to be popularized.

The Calculation of the Lateral Forces on the Slope Supporting Structure Under the Seismic Forces

Shi Weimin

2013, 27(3): 150-153. doi: 10.3969/j.issn.1007-2993.2013.03.010

[Abstract](20) [PDF 366KB](6)

Abstract:
In order to reduce or avoid the losses of slope failures caused by earthquake, it is very necessary to study the slope stability and support issues under seismic forces. To calculate the lateral forces of the slope under the earthquake, the seismic forces as a horizontal force and the direction of the force point to the outside of the slope. With the assumptions that the slide surface is straight line, the lateral forces of slope are deduced by limit equilibrium method, and a general formula of the lateral forces is established. The lateral forces can be used to the design of retaining structures.

Axial Force Processing of Foundation Steel Braces By using Wavelet Analysis

Lin Dongwei, Zhou Yuan, Wang Dexi

2013, 27(3): 154-157. doi: 10.3969/j.issn.1007-2993.2013.03.011

[Abstract](28) [PDF 1277KB](7)

Abstract:
Due to the change of measure environment, measure equipment and subjective of measure person, the measure signal of foundation steel braces contains noise inevitably and has some outliers. The measured signal is a time series made up of different frequency, and was processed by wavelet analysis. Denoising analysis and outliers detecting of the measured signal is performed using wavelet analysis, and proved by a specific project. The result indicated that this method is effictive for denoising analysis and outliers detecting

Study on Subgrade Bearing Capacity of Sand in YiTong River in Changchun

Sun Guangli, Gao Tao, Yu Guangyuan

2013, 27(3): 158-160. doi: 10.3969/j.issn.1007-2993.2013.03.012

[Abstract](27) [PDF 545KB](9)

Abstract:
In order to achieve reliable data about the characteristic value of subgrade bearing capacity of sand of YiTong river basin in Changchun, to approach appropriate measures for determining the characteristic value of subgrade bearing capacity, in-situ testing methods including loading test, cone penetration test(CPT),and standard penetration test(SPT) are carried out for study on the sand and thirteen sets of data whice about characteristic value of subgrade bearing capacity,the value of CPT and blow counts of SPT are collected. Through the statistical analysis of the test data, get the characteristic value of subgrade bearing capacity of the range of the sand. That the characteristic value of subgrade bearing capacity and value of CPT and blow counts of SPT linear related conclusion. According to the conclusion, two kinds of experimental formulas adapting to the local engineering geological condition are proposed, one of which is for determining the characteristic value of subgrade bearing capacity of sand by blow counts of SPT, the other by value of CPT.

Analysis of Drilling in Cobble Layer and Direct Static Sounding in Pre-guide Hole

Li Jianbin, Zhao Junpeng, Zhou Chunhua

2013, 27(3): 161-163. doi: 10.3969/j.issn.1007-2993.2013.03.013

[Abstract](37) [PDF 452KB](6)

Abstract:
To get the physical and mechanical properties of cobble and boulder, you should first find out the compactness, grain size, distribution patterns, contents, and the fillings content. Now, lower construction efficiency, great labour intensity and high cost are the main problems in drilling. Meanwhile, there is a limitation that using dynamic sounding to judge the density of cobble, because it is much higher when drilling the surface of cobble, and lower when drilling the fracture of cobble. Considered with 《Technical specification for engineering geological prospecting and sampling of constructions》JGJ/T 87-2012 attached table G.0.6, the acquired compactness will be more objective. Static sounding generally cannot cross tight gravels, so how to get the static sounding data below them is a difficult problem in our work. Based on several different geotechnical engineering exploration practices, this paper discussed the solutions for the above mentioned problems.

2013 Vol. 27, No. 3