岩土工程技术

Study of the Stability of High Fill Coarse Grained Subgrade Slope Based on the ABAQUS Simulation Analysis

Liu Li

2014, 28(5): 217-220,264. doi: 10.3969/j.issn.1007-2993.2014.05.001

[Abstract](37) [PDF 803KB](7)

Abstract:
The research of the stability of high fill cohesive soil slope was more in the past. In order to study high fill coarse grained soil slope which is different from cohesive soil on the deformation and strength, using software ABAQUS, the multilevel rein forced soil slope was finite element numerical simulated with strength reduction theory and the stability of the whole slope was analyzed The results show that, the reinforced not only improves local stability of each step, but also strengthens the integral stability of slope; the slope has horizontal displacement. The maximum value appears in the slope bottom near the slope toe. And a part of negative displacement appears along the positive X axis; horizontal displacement reduces with the filling height increasing. The largest horizontal displacement is in the first step; closer to the slope, the geogrid and soil displacement are bigger. The trend of becoming large is approximate alignment. But the soil horizontal displacement is significantly greater than the geogrid horizontal displacement.

Application of Dynamic Compaction Replacement Method in Collapsible Loess

Meng Tingwei, Wu Zhian

2014, 28(5): 221-223,270. doi: 10.3969/j.issn.1007-2993.2014.05.002

[Abstract](31) [PDF 633KB](6)

Abstract:
In this paper, dynamic replacement method in collapsible loess foundation applications are discussed. According to the structure of high load bearing capacity of the foundation and the foundation of a low-collapsible characteristics by comparing a variety of programs, dynamic replacement foundation treatment method is selected. Better technical results achieved by detecting, can greatly improve the bearing capacity and eliminate collapsible, and has good prospects for engineering applications.

Integrated Management of Geotechnical Investigation and Survey Results Based on GIS

Wang Jianming, Zhang Jiwen, Liu Zhenghong

2014, 28(5): 224-226,260. doi: 10.3969/j.issn.1007-2993.2014.05.003

[Abstract](52) [PDF 1097KB](8)

Abstract:
In this paper,the investigation results management mode based on the relation database and GIS technology is presented to combine the advantage of relational database for efficient management of massive data with the powerful processing ability of GIS spatial data. This mode realizes the integrated management of investigation data, reports, charts, images and other information. It not only meets the management integration requirements, but also provides the basis for knowledge discovery, expert database and other senior application. Based on the actual system construction as an example, this paper introduces the architecture model, function implementation and system integration of the management information system.

Monitoring and Study for Anchor Tension of Deep Excavation Engineering of Wangjing A1-C-4^# Project

Zhang Qinxi, Liu Xin

2014, 28(5): 227-231. doi: 10.3969/j.issn.1007-2993.2014.05.004

[Abstract](54) [PDF 1147KB](6)

Abstract:
Deep-excavated foundation engineering is common in Beijing area, while the related monitoring and theoretical researches are not quite sound. Through the monitoring and research on bolt pulling force in the supporting project of foundation pit at Land No. 4 Group C, Wangjing Al District, it is deducible that the project is quite distinctive as the pulling force changing tendency of the two lines of bolts are opposite. That reflects in some degree the incompleteness of the current regulations and the strong geographical characteristics of excavation projects. Pile body's displacement monitoring should be introduced to projects so to ensure their safety and to provide detailed data for design optimization and cost reduction. It's recommended that when pulling machinery in construction is available, axial force meter of bolt should be used firstly to quantify the pre-stressing loss locked, and optimize the construction parameter properly in accordance. Therefore, it follows that there exists vast room for optimization for the current excavated foundation engineering. The research result could also provide reference and foundation for similar engineering design.

Analysis of Characteristics of Geotechnical Engineering of Coral Reef

Cui Yongsheng

2014, 28(5): 232-236. doi: 10.3969/j.issn.1007-2993.2014.05.005

[Abstract](37) [PDF 766KB](8)

Abstract:
Based on the results of field survey and plate load test, the coral reef was classfied as oceanic coral reef and coastal coral reef, and the rules of nomenclature incoral reef was provided further. According to the results of the field plate load test, the characteristics of geotechnical engineering of coral reef were analysised. The results of this paper provided effective references for study on the characteristics of geotechnical engineering of coral reef and engineering practice.

Deep Fill Layer with Sizable Area Foundation Treatment Technology for Tall Buldings

Chen Jianmin

2014, 28(5): 237-242. doi: 10.3969/j.issn.1007-2993.2014.05.006

[Abstract](32) [PDF 1055KB](7)

Abstract:
With the development of urbanization in China, the high quality construction land has been significantly decreased. Rational utilization of defective land resources is a great subject of urban development faced at present. In urban expansion process, we often meet sandstone pit or weak soil area, and the foundation treatment method and result will affect construction cost and superstructure quality security. The foundation is a sandstone pit with a wide range of depth of 17 m. A new foundation treatment technology for sandstone pit with sizable area was introduced. Practice proves that it is an economic and effective method of ground treatment and has fulfilled the design requirements of the stability of soil bearing capacity.

The Research on Optimization Design of Toe Slab Foundation Plane of Tianchi Pumped Storage Power Station

Bi Dan, Wang Zhongfu

2014, 28(5): 243-249. doi: 10.3969/j.issn.1007-2993.2014.05.007

[Abstract](21) [PDF 4472KB](4)

Abstract:
By combination of survey data and field investigation of the Tianchi pumped storage power station dam, the distribution of altered rock was researched. By use of thin section identification, scanning electron microscope and X-ray diffraction analysis test, the altered rock of rock composition and chemical composition was analyzed. The geological causes of alteration and alteration mechanism was studied and the physical and mechanical parameters of altered rocks were obtained with laboratory experiments; altered rock riverbed toe slab foundation is numerically calculated and analyzed by using FLAC3D software in the different conditions and the different elevations. The results show that:on the left bank and right bank of the maximum depth of weathering is not as strong and the proposed excavation and toe slab foundation was in the bar in the middle of the mixed granite; the alteration of sand-like core presented in the range of dam foundation F₂₅ fault and around the fault zone is the main geologic factors of dam deformation and the adverse impact of the dam settlement; the numerical simulation of river altered rock toe slab foundation optimization showed that the riverbed of the 930~950 m elevation being as base surface is appropriate.

Boundary Problem and Its Influence to Vacuum Preloading

Gao Zhiyi, Feng Jun

2014, 28(5): 250-256. doi: 10.3969/j.issn.1007-2993.2014.05.008

[Abstract](34) [PDF 2032KB](7)

Abstract:
In this paper, the definitions of open and closed boundary are presented firstly. The differences of both are discussed. Through three samples,the reason for open type boundary being better than closed boundary in reinforced effect is analyzed. Then,it is shown how to convert closed boundary into open boundary. Secondly, it is present that the flexible and rigid sealing membrane can also made up open and closed boundary. The differences of both are discussed. Thirdly, the definitions of sealing wall and the retaining wall, the function and application scope are given. Finally, the cement wall and the geogrid wall forming by cement mixing pile and jet grouting pile are introduced respectively. Through discussing their definition, function and application scope, the former is only as sealing wall, and the latter is not only as sealing wall but also as retaining wall.

Effect of Groundwater on Sand Slope Stability

Zhang Xiaocheng

2014, 28(5): 257-260. doi: 10.3969/j.issn.1007-2993.2014.05.009

[Abstract](48) [PDF 4943KB](8)

Abstract:
Inner Mongolia in winter snow is thick, the spring temperatures rise quickly, a lot of snow water in slope and retaining wall back in fine sand layer. Due to the drainage hole at the upper part of the lower slope and retaining wall most jam, water can not be discharged. Melting snow along the slope surface flow, resulting in instability of slope deformation. The rise of ground water level, serious water retaining wall, according to the principle of soil into account in calculating soil pressure on retaining wall, retaining wall is easy to slip.

Experimental Study of Electro-osmotic Test

Wang Ningwei, Han Xu, Zhang Lei

2014, 28(5): 261-264. doi: 10.3969/j.issn.1007-2993.2014.05.010

[Abstract](21) [PDF 974KB](4)

Abstract:
According to a lot of laboratory tests,generally master the law of level electro-osmotic drainage of the unsaturated cohesive soil with different electric potential gradient. Do some electro-osmosis curve analysis about the aspects of electro-osmosis displacement, drainage rate, soil resistance, coefficient of permeability of electricity, energy consumption and energy dissipation coefficient. The theoretical basis about electro-osmosis method for the future of the actual operation is given according to the termination conditions of electro-osmotic drainage determined by the analysis approximately. The results show that soil resistance increases and electric current decreases with the increase of conduction time. It leads the decrease of the electro-osmotic drainage rate. Electricity can be stopped in the end of electro osmosis for reasons of energy saving. It benefits electro-osmotic drainage and saves energy.

Experimental Study on Uplift Pile Bearing Capacity in Shenyang Sand Gravel-Clay

Zhang Quansheng, Liu Qi, Liu Zhongchang

2014, 28(5): 265-270. doi: 10.3969/j.issn.1007-2993.2014.05.011

[Abstract](28) [PDF 1077KB](7)

Abstract:
Through static load test, inforcement stress tests and other tests on uplift pile in Shenyang sand area, study the uplift pile bearing capacity and lateral friction, and get the following conclusions:according to the soil division by stratigraphic to determine the lateral friction is more reasonable than the soil division by lithology; before and after grouting, the lateral friction enhancement factor is about 1.15 to 1.62 in the enhanced part; the effect of branches and plates can partly improve the lateral friction, but also limit the lower lateral friction in certain length range of the pile.

2014 Vol. 28, No. 5