岩土工程技术

The Experimental Study on Materials of Sea Water Slurry for Bored Pile

Liu Jingjing, Li Tiansheng, Wang Wei

2016, 30(4): 163-165,198. doi: 10.3969/j.issn.1007-2993.2016.04.001

[Abstract](104) [PDF 925KB](9)

Abstract:
In coastal bored pile construction, using fresh water slurry will be polluted by sea water, and affected slurry performance. Because the fresh water resource is limited, the cost of the fresh water slurry is very high, If we can use directly the sea water to mix slurry, this method can greatly reduce the difficulty and cost of the slurry. According to a lot of laboratory tests, Biological xanthan gum (XC) can be used as a viscosifier of seawater slurry, the performance of sea water slurry is better than other viscosifier, and the cost is very low.

Case Analysis of Using Combined Excavation Methods to Demolish the Whole Shield Segments

Zhang Li, Zhang Xiaowei, Du Nanxin

2016, 30(4): 166-169. doi: 10.3969/j.issn.1007-2993.2016.04.002

[Abstract](55) [PDF 2842KB](9)

Abstract:
Subway construction as a large long linear engineering project, the risk of time limit for a project is increas ingly prominent in recent years, adding station, canceling station or postponing station is common. So the combination using of various excavation method is an urgent needing, to solve the new problems caused by the plan adjustment, to meet the operating function under the premise of effective control time limit for a project. Based on Beijing subway line 10 second phase Liuliqiao station--Maguanying station (delayed) Lianhuaqiao station interval for the engineering example, this paper detailed interprets the method of shield segment removed and Air duct implementation after the shield tunneling ahead and track-laying. For similar project and feasibility study on implementation of postponed station, it has the reference significance.

Finite Element Analysis of the Secondary Reinforcement Design of Deep Foundation Pit Based on the “Space Effect”

Lu Keyan, Yao Aijun, Zhang Jiantao

2016, 30(4): 170-175,185. doi: 10.3969/j.issn.1007-2993.2016.04.003

[Abstract](69) [PDF 24027KB](9)

Abstract:
Through numerical simulation, the appropriate secondary reinforcement modes and reinforcement ranges have been studied in this paper based on the soil layer structure of a typical deep foundation pit in Kunming, Yunnan province. As shown by calculation, when the one section reinforcement scheme is adopted at the central of foundation, the horizontal dis placement of foundation pit wall scarcely increased after the secondary reinforcement range larger than 0.54l(l:the length of foundation pit sidewall), when the two section reinforcement scheme is adopted at the central of foundation, the horizontal dis placement of foundation pit wall scarcely increased after the secondary reinforcement range larger than 0.18l. The two section reinforcement scheme is superior to the one section reinforcement scheme on the cost and reinforcement effect. The results of this paper providing a reference to similar projects.

The Advanced Support Construction Technology of the Shallow Tunnel with Uneven Characteristics of the Poorly-graded Sand

Wang Wenbing

2016, 30(4): 176-179,192. doi: 10.3969/j.issn.1007-2993.2016.04.004

[Abstract](37) [PDF 2931KB](8)

Abstract:
Based on the underground excavation engineering of Liaogongzhuang station on the west extension project of Beijing metro line 6, center about the uneven characteristics of the poorly-graded sand, the instable structure, the crushed gravel layer and the pebble stacking, and the own risk of the shallow tunnel. By comparison, determine to adopt the double tube WSS retreating deep hole grouting technology to pebble stratum, introduce thematerials of deep hole grouting technology, the machines, the grouting pressureand the detail process etc. Aiming at providing some experience and reference to the similar projects.

Numerical Analysis of Deformation on Combined Retaining System of Soil Nails and Pile-Anchors

Zhang Kai, Zhang Qinxi, Zhang Qibing

2016, 30(4): 180-185. doi: 10.3969/j.issn.1007-2993.2016.04.005

[Abstract](57) [PDF 2720KB](14)

Abstract:
In recent years soil nails and pile-anchors has been adapted to pit slope engineering of urban agglomeration space. The research of deformation of soil nails and pile-anchors with excavating and stable still needs to discussing about. It is inseparable from a pit projects, which researching the regularity of deformation about supporting structure and foundation of soil nails and pile-anchors. Analyzing 1-1 section of the B43 pit project-Wandefu square for Pinggu with participated by FLAC^3D finite difference software. By compared with the actual measurement, FLAC^3D simulation can conclude some conclusion, such as the displacement of pile anchor block more than soil nails, the displacement of pile anchor increasing with excavated and the after paragraph displacement larger, while two ends displacement smaller for the pile presents itself. Additional the foundation pit can be uplift with excavating. By compared with data of actual measurement, the results by FLAC^3D is coincide.

The Improvement of Spencer Method on Slope Stability Analysis

Liu Xiujun

2016, 30(4): 186-188. doi: 10.3969/j.issn.1007-2993.2016.04.006

[Abstract](84) [PDF 551KB](18)

Abstract:
Based on the classical earth pressure theory to set the thrust line of soil article, the relationship between the lateral interaction force of soil article can be derived from the torque balance equation, consider the conditions which the lateral force of the first and the end soil article parallel to the top when the soil article is small enough, combined with the boundary conditions for solving the "P_i" and "θ", substituting them into the definition of the safety factor to obtianed the safety factor. The law solving the "θ" starting from setting a reasonable thrust line, eliminating the blindness and complexity of the Spencer method to assumes the "θ",to fix the "θ" of the first and the end soil article, making the results closer to the real solu tion. Examples show that the method is simple in calculation, reliability and has other advantages.

Analysis and Effect of Dynamic Compacting in Backfill Consolidation

Mu Lei, Li Lianying, Guo Meng

2016, 30(4): 189-192. doi: 10.3969/j.issn.1007-2993.2016.04.007

[Abstract](61) [PDF 1337KB](14)

Abstract:
As an important method of foundation treatment, dynamic compacting method is used in construction engineering filed widely owing to its advantage. This paper tests the foundation bearing value of a pit in Tianjin city by taking Static load test, the drilling, SPT, CPT, indoor water testing and other ways of comprehensive investigation and proves that it is reasonable and feasible to use dynamic compacting to deal with backfill.

Application of Strength Reduction Method in Pump Room Slope Analysis of Certain Nuclear Power Plant

Ma Bo, Gu Shengquan, Ge Honghui

2016, 30(4): 193-198. doi: 10.3969/j.issn.1007-2993.2016.04.008

[Abstract](55) [PDF 2733KB](12)

Abstract:
Firstly adopt limit equilibrium method and strength reduction method to carry through two-dimensional analysis of slope stability, and contrast analysis result to validate veracity and feasibility of strength reduction method. Secondly contraposing the three-dimensional influence of slope excavation, reinforcement and tunnel excavation, adopt three-dimensional elastoplastic FEM strength reduction method to analyse slope stability, analyse the safety factor, E-equivalent strain, displacement distribution and major stress distribution. The result indicates that reinforcement measure may obviously improve safety factor of slope stability, and three-dimensional strength reduction method is obviously preponderant in rock and soil engineering domain.

Discussion of RD 8000 Using Methods in Detection of the Underground Pipeline

Xu Jiaohuang

2016, 30(4): 199-202. doi: 10.3969/j.issn.1007-2993.2016.04.009

[Abstract](57) [PDF 1056KB](6)

Abstract:
Base on the work principle of RD 8000 underground pipeline detector, this paper expounds the use of different methods and the advantages and disadvantages between RD 8000 underground pipeline detector using methods, analyzes the error of the underground pipeline detection, and analyzes the locating error size in Peak and Valley locating methods. Finally, some suggestions are put for the detection of the actual underground pipeline by using RD 8000.

Foundation Bearing Capacity and Geological Characteristics of Yanbian Helong

Li Xiangqun, Yuan Chengwang

2016, 30(4): 203-206. doi: 10.3969/j.issn.1007-2993.2016.04.010

[Abstract](82) [PDF 815KB](13)

Abstract:
Research on foundation bearing capacity and geological characteristics of Yanbian Helong is little, based on geotechnical test, heavy dynamic penetration test and standard penetration test in situ testing method, Helong area often used gravel layer and weathered mudstone layer in engineering, got round gravel granular layer gradation, foundation bearing force characteristic value, de-formation modulus data, weathered mudstone foundation bearing capacity characteristic value of the data. The test dma for statistical analysis, draw Helong area round gravel layer foundation bearing force and draw round gravel layer foundation bearing force characteristic value, deformation modulus and heavy cone dynamic penetration hammer number linearly related to the conclusion, so as to establish the local geological conditions related to the empirical formula, empirical formula. To Helong area geotechnical engineering exploration ensure access to reliable, applied geotechnical parameters provide experience and evidence, provide experience for similar area.

Stability Analysis of Deep Foundation Pit in Fault Zone

Zhang Qinxi, Liu Hang, Shi Chaodong

2016, 30(4): 207-211,217. doi: 10.3969/j.issn.1007-2993.2016.04.011

[Abstract](73) [PDF 2538KB](9)

Abstract:
The design and excavation scheme of deep foundation pit should be considered seriously, in complicated engineering geological conditions and the surrounding environment, otherwise it will cause a great impact on the foundation pit support and even the whole building. The geological conditions, landslide inducing factors, and the process of formation and development of the landslide was studied thoroughly in this paper. The factors affecting the stability of the foundation pit was revealed, combined with monitoring date.

A Simple Settlement Calculation of Single Pile Based on Field Load Test

Liang Jinguo, Ding Jihui, Liu Hongchao

2016, 30(4): 212-217. doi: 10.3969/j.issn.1007-2993.2016.04.012

[Abstract](42) [PDF 1614KB](14)

Abstract:
Based on the distribution of pile's axial force under vertical loads, this paper analyzes the bored plie's bearing characteristic/the load transfer law along the pile body/the distribution of axial force for pile section/the distribution of the side pile resistance under vertical loads, and the calculation results are consistent with the measured results. Starting from the Q-s curve of single pile to determine the soil deformation curve below the pile end plane under various stepwise loadings, then using the deformation curve can easily calculate the single pile settlement, and the calculation results are consistent with the measured results of single pile load test. Using the distribution function for axial force to calculated the compression of pile body and the settlement of the pile toe, then we will calculate the settlement of single pile, the results are consistent with the results by using the field test data to calculate, and the results are smaller and they may satisfy the engineering demand.

2016 Vol. 30, No. 4