Study On Application Of Jet Expansion Head Anchor In Foundation Pit Project In The Di Yi Square

In recent years,the pile-anchor support in deep foundation pits is put to use widely.The bursa type anchorage cable used in deep foundation pit of expansive soil is protected by its patent,for this reason,it's expensive,in which field needs technical breakthroughs to achieve a breakthrough in economic benefits.The technology of spinning and sprouting head anchor is a new anchor technology,which has the advantages of fast construction speed,lower construction equipment requirements and better economic benefits when compared with cystic anchorage cable,but there is no precedent in the application of deep foundation pit supporting engineering in Chengdu expansive soil.Relying on the deep foundation pit of expansive soil in the east of Chengdu,the paper researched the economic benefits of jet grouting,the influence parameters of jet grouting,the stability of foundation pit and anchor cable as well as the failure mode of anchor cable by economic analysis,field tests,tensile test of anchorage cable,displacement monitoring of the pit and the buildings nearby,axial force monitoring of the cables and numerical simulation.The main conclusions are as follows:Through the analysis of construction's costs and the time's limits,we could come to a conclusion that the high pressure large head anchorage cable have better economic benefits.According to the field's tests data,the relationship between the circumference of the anchor solid and the jet pressure in this soil is L=0.66P+80(L is anchor solid perimeter,P is the jet pressure);the relationship between the circumference of the anchor solid and the jet time is L=0.5t+83.39(t is the jet pressure),which could guide the field construction;pullout resistances of the cable are more than 800 k N without any destruction;the horizontal displacement values of the pit are under the limit,the sedimentations around the pit are safe,the sedimentations of the buildings nearby are normal;the axial forces monitoring of thecables in the whole life cycle are finded no loss and slack,which shows a good stability;the numerical simulation in FLAC3 D shows the failure mode of the cable is conforming to conditions existing.