Construction Technology of Deep Foundation Pit Support in Municipal Civil Engineering Foundation Construction

Municipal civil engineering is the key content of municipal construction,and the construction scale is usually large.The quality of the project plays an important role in the development of urban economy.Due to the rapid increase of high-rise buildings,skyscrapers and underground buildings,the construction technology of deep foundation pit support has gradually become an indispensable construction technology.Therefore,the selection of foundation pit support construction technology is crucial in ensuring that whether the foundation is firm and stable,and whether the subsequent construction activities can be carried out smoothly.In view of this,the article discusses the application of deep foundation pit support construction technology in municipal civil engineering,aiming to provide reference for subsequent projects.

Numerical Simulations of Pile Supported Protective System Subjected to Ship Impact

The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA. The influences of pile non-linearity and soil non-linearity on impact force, ship crush depth and the cap displacement of pile supported protective system are discussed. It's shown that for both severe impact case and non-severe impact case, the non-linearity of pile material influence the impact force history, ship crush depth. The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case. These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.

Seismic response analysis of GRPS embankment under oblique incident P wave

In order to investigate the seismic performance of geosynthetic reinforced and pile supported(GRPS) embankment under seismic loads, an input method for three-dimensional oblique incidence of P wave was proposed. This method is based on the explicit finite element method while considering the viscous-spring artificial boundary(VSAB) condition. Using the proposed method, a numerical study was conducted, and the influence of oblique incidence on the seismic response of GRPS embankment under the oblique incident P waves was analyzed. The results indicate that in comparison with vertical incidence, the oblique incidence can significantly increase the displacement, velocity and acceleration of key locations in the GRPS embankment. The existence of geosynthetics can alleviate the impact of seismic load on the response of the embankment to a certain degree. Moreover, the number of reinforcement layers and modulus of geogrid also greatly influence the seismic performance of GRPS embankment.

Field study on performance of new technique of geosynthetic-reinforced and pile-supported embankment at bridge approach

Vehicle bumps at a bridge approach caused by the differential settlement between a bridge and an adjacent backfill embankment are one of the most difficult problems in geotechnical engineering. Large vehicle bumps make drivers uncomfortable and cause large impact loads on vehicles and the bridge abutment. A new ground-improvement technique called fixed-geosynthetic-reinforced and pile-supported embankment(FGT embankment) was developed and used to alleviate vehicle bumps at a trial bridge-approach site located in central China. To distribute the differential settlement between the bridge and adjacent backfill embankment over a long transition zone, the following three techniques were used at the trial bridge-approach site:(a) the FGT embankment,(b) conventional geosynthetic-reinforced and pile-supported embankment(CT embankment), and(c) geosynthetic-reinforced embankment without piles(GR embankment). The performance of all three techniques in the field trial was investigated by field measurements involving earth pressure cells, geosynthetic deformation sensors, and settlement gauges. The FGT and CT embankments exhibited better performance than the GR embankment. Compared with the CT embankment, the FGT embankment was more effective at ground improvement. At an elevation of 4.0 m from the base of the embankment, the pressures below the geosynthetic were smaller than those above the geosynthetic at the closest measurement point. The difference between the pressures between above and below the geosynthetic tended to increase with the embankment height.