| In 1991, the Ministry of Communications functioned as the planning of the national arterial highway made a plan which called five verticals and seven horizontals. In 1991, the highway was only several hundred kilometers, and up to last year there are already 50,000 kilometers. Every year there are several hundred billion used in the expressway in the whole country. By 2008, national road of our country is up to 3,573,000 kilometers, at the mean time, a large amount of national roads are being reconstructed.Relying mainly on soft soil in the east coastal area of our country, this puts forward new subject on reconstructing the arterial highways. Because the abutment built on the soft soil ground usually adopts pile foundation, settlement is very little, and construction that link with it usually make amount settlement in soft soil ground. Looking from constructed projects, there is usually some settlement after construction, abutment and embankment store obvious difference in settlement, cause vertical slope sudden change, produce car jump on the either end of a bridge. Either end of a bridge jump car make vehicle is it beat and strike to produce when passing, lead to the fact the additional impact to load to the bridge and road surface, and make the department feel jolt and uncomfortable to ride personnel, the serious one makes the vehicle passing moderate by a large margin, some even cause the accident, the normal operation of the influence highway, will obviously reduce the economic benefits of the highway and social benefit. At present, DMJ PILE is mainly used to improve the ground on the either end of a bridge in order to preventing car jump.When using composite foundation to deal with car jump on the end of bridge, the quantity of DMJ pile plays a key role to the efficiency of improvement. DMJ pile is made of several materials, such as cement , lime ,etc. as the solidification pharmaceutical. The material is spurted into the soil of the ground by compressed air. With the rotation of the blade , the powder materials and soft soil are fully mixed, and form the post form with certain intensity and strengthen the cement soil , thus improved the strength of the ground . The functions of DMJ PILE mainly include body function, cushion function, crowding dense function, reinforcement function. The DMJ PILE construction technology mainly includes construction craft, quality control and quality inspection.Through situ testing, it shows that the total settlement is obviously reduced after improvement by DMJ PILE on the end of bridge, at the same time because the DMJ PILE composite foundation has not drained off water in the pass way, it is relatively slow to subside steadily, but always subside small after the construction, and is smaller than the designing requirement of 10cm. According to observing results, the compression of high embankment itself can't ignore. Because of the soil is structural, a critical height of the fill exist, when fill height is bigger than this value, the structure of the soil will be destroyed, and settlement will accelerate. After dealt with DMJ PILE, the critical height of fill increase, about 3m , and relevant load about 60kPa. After dealt with DMJ PILE, fill out the ultra quiet hole caused in the soil of the ground in land and press generally smaller, but it is slow to dissipate, the side direction displacement of the ground is obviously reduced, help to reduce to the horizontal thrust of one of base of the abutment. The greatest horizontal displacement has line sexual relations with very high dependence with subside. Whole pigeonhole, maximum, soil of pressure fill out improvement loaded in soil increase at the same time. Of soil stress than little, soil ultra quiet hole pigeonhole heavy, is it lie one layer of ultra quiet holes pigeonhole little to make, soil stress is more opposite than greatly. DMJ PILE by meet an emergency the bodies (namely stress) with on change and the of growth, body of intensity loaded to cover more change, a body meets an emergency and fills out the increase loaded in land at the same time there is obvious lagging, the whole of the ground out of shape of a body is out of shape and relevant, its change law remains to study further. Experimental study indicates that it is feasible to adopt DMJ PILE to deal with and reduce the difference of highway section of the either end of a bridge to subside.A lot of mechanics problems in the engineering field, can all be summed up in and given border conditions definitely and often ask solving differential equation and question leaning towards differential equation basically. Though can receive their basic equation and border condition under certain condition , but the one that can be totally analyzed and solved is only all simpler problem of a few nature and border condition , and the form of the real structure and load received are often more complicated, it is difficult to be analyzed and solve . Solving this kind of complicated problem has two kinds of methods mainly. First we can make some suppose and then make question simplify , solve to analyze to appear to ask or half analyze and solve to introduce; Second , carry on the approximate solution that the numerical simulation tries to get the question to the already existing complicated problem. Numerical simulation technology is on the basis of modern mathematics, theory of mechanics, obtain the number value approximate solution that all over foot project require with the aid of the technology of the computer. Large-scale finite element software ABAQUS is extensive while applying the rock soil project finite element to and analyzing at present. Tested the situation and built the model of setting up and utilized ABAQUS finite element software to gush out one and compound to the powder living, the loading course of the ground imitate analyzing. Whether for modeling of facilitating, is it assume while being the following to make to real project.1) utilizing symmetrically, analyzing with plane strain;2) without considering the friction between the pile and soil around the pile;3) pile and fill are elastic, soil is homogeneous, saturated, and perfectly elastic plastic;4) the deformation of fill itself is very small ;During the stage of loading, it is comparatively obvious to subside and develop. After completion of loading, subside and develop speed relatively low , and tend towards stability. The deformation of the strengthening area (1, 2 areas of soil layer) is relatively small, it is on the bottom to subside and happen mainly and lie on story (soil layer 3, 4, 5). Among them, 11.8% subsiding finally and accounting for and always subsiding of the strengthening area, soil layer 3 accounts for 36.7%, soil layer 4 accounts for 27.1%, soil layer 5 , 6 accounts for 24.4%, and the thickness of soil layer 4 only has 2.5m, the occupation rate is very great that subside, on one hand prove the depth of influence of the additional stress is very large , to this project, additional stress value for depth when the heavy 0.2 that load 78m about most, calculate when subsiding must is it lie subsiding amount of layer to down to pay attention toeing, is it subside to control notably to want to prove on the other hand, must big range weak soil layer is punish to go on to additional stress.The result shows that it is on the bottom to subside to happen mainly, during the stage of loading, the settlement development is very fast, after completion of loading, the settlement development is relatively slow, tend towards stability finally. So improvement can quicken the development of ones that subside to add the speed of...
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