Xian China Highway Geotechnical Engineering Co.
Xian China Highway Geotechnical Engineering Co.
Liu N.,Chang'an University |
Liu N.,Key Laboratory of Western Chinas Mineral Resource and Geological Engineering |
Huang Q.,Chang'an University |
Huang Q.,Key Laboratory of Western Chinas Mineral Resource and Geological Engineering |
And 10 more authors.
Soil Dynamics and Earthquake Engineering | Year: 2017
This paper studies the seismic response of a segmented metro tunnel with flexible joints passing through active ground fissures in Xi'an by shaking table model test. A coupling dynamic ground motion was generated in the test model. The tunnel acceleration, earth pressure and tunnel structure strain were monitored and compared. It was observed that each part of the tunnel has an independent movement with flexible joints. The tunnel located in the hanging wall has 3.17 times peak acceleration than that in the foot wall. Higher magnitudes of earth pressures were recorded close to the areas of the ground fissures. The earth pressure in the hanging wall was greater than that in the foot wall. The coupling loads increase the earth pressure. The strain in the middle of the tunnel arch was the largest. The strain at the bottom of the floor was the secondary. The one on the top of the arch was the smallest. The strain increased less in each section because the tunnel is divided into four parts by flexible joints, and no sharp strain increase close to the ground fissure was observed. The results indicate that the flexible joints can decrease the stress concentration. The tunnel with flexible joints can adjust to large deformations in the ground fissure areas. © 2017
Li Z.-S.,Chang'an University |
Li X.-S.,Chang'an University |
Gao H.-Y.,Xian Metro Co Ltd |
Zhang F.-Z.,China Railway First Survey and Design Institute Group Ltd |
And 3 more authors.
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2013
The ground fissures were studied in details along Xi'an metro No. 1. On the basis of previous research data collection and ground investigation, the research was implemented mainly by means of drilling exploration which could reveal strata situation of ground fissures of both sides and then the fissures' locations and characteristics were determined. The results show that the Xi'an ground f3, f4, f5 cross the metro line, and f3 crosses twice. In addition to the Xi'an ground fissures, two ground fissures, Chao-yang-men-wai and Pao-ma-chang-Fang-zhi-cheng also cross the metro line, and the latter intertwines the metro line and passes through it 3 times. The Chao-yang-men-wai ground fissure has not been discovered before. It has the same properties with those of Xi'an ground fissures and has great displacement of fault according to the drilling profiles. Pao-ma-chang-Fang-zhi-cheng ground fissure is over 4 km long. It outcrops two banks of Chanhe River, and has the same activity with Xi'an ground fissures, therefore should be listed in Xi'an ground fissures' category.
Li Z.,Chang'an University |
Gao H.,Xian Metro Co. |
Song Y.,Chang'an University |
Li X.,Chang'an University |
And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2013
Chang'an ground fissures along the fourth metro line of Xi'an city inside the Lintong-Chang'an fault zone were studied by ground survey, drilling exploration and trench investigation. Two drilling profiles show that the fissure abnormities may occur at topographic place with the maximum elevation gradient and the paleosol stratum beside the two sides of abnormities have obviously vertical drops. The excavation of one large-scale trench reveals following facts: (1) the fissure zone is composed of one major fracture and several junior cracks and the major fracture is well developed and parallels to Lintong-Chang'an fault zone; (2) the southeastern wall of the major fracture is relatively declined and inclined to the southeastern with dip of 80°~85°, which is opposite to the Lintong-Chang'an fault; (3) the palaeosol layer of two sidewalls is dislocated with 1.1m displacement and the downthrown side stratums of major fracture are thicker than those of the uplifted side. The investigation and research results show that Chang'an ground fissures develop in particular loess landform area inside the Lintong-Chang'an fault zone and emerge near the place with the maximum elevation gradient in the southern side of loess swale and induced by deep tectonic activity. Similar to Xi'an ground fissures according to the fault style and developing mode, Chang'an ground fissures appear as the characteristics of both normal fault and growth fault in general.
Yu X.-Y.,Chang'an University |
Yu X.-Y.,Xian China Highway Geotechnical Engineering Co. |
Wang X.-M.,Chang'an University |
Huai C.,Xian China Highway Geotechnical Engineering Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010
Based on the theories of the limit equilibrium and limit analysis approaches, a new calculation model is presented, which can consider the effect of ascent of fill section at the back of slopes. A new upper limit formula is deduced, and its results are compared with those of the finite element method and other upper limit calculations. The analytic results show that the upper limit solution is close to the real solution, and it can reflect the ultimate bearing capacity of the real sloping ground. Besides, with the program which can calculate the mobilization factor of the fill section at the back of the sloping ground, the effect is analyzed, including angle of internal friction of the sloping ground, underside slope angle, upside slope angle, relative distance from the edge of slopes and relative depth of footings. The bearing capacity factors and mobilization factor of the fill section at the back of the sloping ground in different conditions are gained. The study results can be used in theoretical analysis of sloping ground, and provide some beneficial conclusions for the design of sloping ground.
Shi Z.-P.,Xian China Highway Geotechnical Engineering Co.
Journal of Chengdu University of Technology (Science and Technology Edition) | Year: 2015
At present, the additional stress coefficient at any point of the rectangular foundation subsoil under the vertically even distributed load is mainly obtained by the corner point method with the help of the "table look-up" and the interpolation. Although the method seems to be easy to use, the results may vary from person to person. In this paper, the author uses the integration method derivates the computational formulas about the additional stress coefficient at any point of the rectangular foundation subsoil under the vertically even distributed load. Moreover, The author also presents some specific formulas for calculating a corner point, a central point, a mid-point on the long side as well as a corner point of a 2ZX26 region beyond the rectangular foundation. By comparing with the formulas for the additional stress coefficients under the corner points listed in the related literature, it is found that the derivated formulas in this paper are completely correct. Although the formulas seem complicated, they are easy to use with the help of the Excel Program Calculation Sheet. They can avoid the interpolation values differences due to different users and the possible confusion due to different rectangle area of lib and z/b during the calculation by the corner point method. As long as the length I and width b of the rectangular area are given, the additional stress coefficient at any point of (x, y, z) can be calculated, which, to some extent, makes the rapid calculation possible. Therefore, the formulas can be very conveniently applied to the practical work for the engineering technicians.