| As a common disease in highway engineering,the problem of bump at bridge-head has a great negative impact on the overall traffic order,driving safety,the later maintenance and management of the highway.Therefore,how to effectively alleviate or even solve this phenomenon is a longstanding issue in the field of highway engineering.For the bridge head part,the bridge head slab can effectively alleviate the faulting problem caused by uneven settlement between the road surface and the bridge abutment.However,in the case of soft soil foundation,the slab is likely to produce a series of new highway hidden dangers,such as the slab fracture and the slab bottom empty.Nowadays,in the treatment of bridge head roadbed in soft soil area,foamed concrete is very commonly used in the treatment of bump at bridge-head in soft soil roadbed due to its excellent characteristics such as excellent energy absorption efficiency,convenient construction and light weight.Therefore,starting from the actual project,this paper proposes a new method of replacement and treatment of high-strength foamed concrete,so as to relieve the bump at bridgehead,solve the problem of secondary jumping and replace the bridge head slab.The main research work of this paper is as follows:(1)Based on the reconstruction and expansion project of Shuikou to Baisha section of Shenyang to Haikou national expressway in Guangdong province,the parameters such as the foundation of soft soil compression modulus,internal friction Angle and cohesion,void ratio and pavement,subgrade materials elastic modulus,poisson's ratio and road cross-section,pavement parameters such as size of each layer.The geological parameters of abysses foundation of K3159+293 bridge in K3157+399-K3165+654 soft soil foundation section were determined by geological drilling.(2)Based on the frequency curve of transverse distribution of the wheel track,by the high strength of foam concrete as material,design three kinds of high strength of foam concrete method:basic model A,basic model B,basic model C.By using ABAQUS software to carry on the three kinds of model and slab method of pavement,subgrade and foundation design reference period of 15 years after the settlement of the numerical simulation,and the subsidence data contrast analysis.The analysis results showed that: on the processing section,three basic models for pavement,subgrade and foundation settlement control are better than that of the slab,but there are basic model A transverse subsidence uneven phenomenon.(3)Through the DLOAD subroutine module,the dynamic response of moving vehicle load is simulated for the expressway model treated by the basic model and the expressway model treatedby the slab method,and the maximum principal stress at the weakest position of the basic model was compared with the mid-span position of the lap plate loading zone.The surface of the analysis results shows that the maximum principal stress peak at the weakest position of each basic type foundation is basically smaller than the maximum principal stress peak at the midspan position of the lat loading zone,and the basic type B and basic type C,which are optimal in the dynamic response at each design speed,are determined.(4)Through the cycle amplitude curves of ABAQUS to simulate under cyclic loading,basic model method and slab method for the control of subsidence of road surface,the results show that: under the cyclic load,the pavement of each basic type can basically recover to the initial state of no settlement;the peak value of the pavement settlement of each basic type under the cyclic load is less than the peak value of the pavement settlement treated by the slab,and the pavement treated by the slab has the settlement that cannot be recovered. |
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