CN106400849A - Sedimentation analyzing method based on pile foundation character analysis - Google Patents

Abstract

The invention relates to a sedimentation analyzing method based on pile foundation character analysis. A load transmission method and a shear displacement method are combined for conducting pile foundation character analysis, a load-displacement-time three-dimensional function graph is drawn, the quantitative relation among the load, the displacement and the time is established, and overload pre-pressing construction is instructed. According to the sedimentation analyzing method, the quantitative relation among the load, the displacement and the time can be provided, the solidification process of a new bridge part is accelerated through an overload pre-pressing method before a new bridge and an old bridge are connected, so that the later-period sedimentation deformation of the new bridge part is reduced, the additional stress of the structure is relieved, and normal use and the safety performance of the bridge are ensured.

Description

Sedimentation analytic method based on pile behavior analysis

Technical field

A kind of the present invention relates to pile foundation settlement field, more particularly, it relates to sedimentation parsing based on pile behavior analysis Method.

Background technology

Latter stage in 20th century, the whole nation after large-scale engineering construction, through the high speed development in more than 20 years, city newly building bridge Speed tends to relaxing, and scale also gradually tapers up.And with economic rapid development, what the Large scale construction later stage gradually manifested asks Topic is：Original bridge can not meet volume of traffic demand quickly, thereby results in traffic congestion and structural overload, and reducing Urban Bridge makes With life-span and security performance.Thus, transformation need to be carried out to original bridge to widen.

During bridge widening, old bridge runs process through the several years after building up, and the sedimentation and deformation of pile foundation tends to relaxing, ground The consolidation process of base enters latter stage, and structure is more stable.In widening project although old bridge sedimentation for surrounding ground There is certain impact, but the ground consolidation process of new bridge portion still with old bridge having differences property of part, sedimentation and deformation is inharmonious, In whole bridge after widening, the sedimentation and deformation process of new bridge portion is partly faster than old bridge, thereby results in the old and new's bridge connecting portion and produces Additional internal force, accelerates the crack of concrete to produce and develop, is finally radiated to surface bitumen layer, causes the cracking of bitumen layer to break Bad, affect bridge service behaviour and traffic safety.

And generally, new bridge static balance time is typically all long, it is the reduction of erection time, improves efficiency, need short New bridge is made to complete to settle in time.Pass between pile top load and pile head settlement displacement be can only obtain according to existing analysis by sedimentation System preloads it is impossible to intuitively determine how to new pile foundation.

Content of the invention

The technical problem to be solved in the present invention is, provides a kind of sedimentation analytic method based on pile behavior analysis, can count Calculate the 3-D quantitative relation of load-sedimentation-time.

The technical solution adopted for the present invention to solve the technical problems is：Construct a kind of sedimentation based on pile behavior analysis Analytic method, comprises the following steps：

S1, to set up the micro unit equation of static equilibrium according to Load Transfer Method and shear displacement method as follows：

Wherein：E is pile foundation Young's modulus, and A is pile foundation sectional area, and i is the soil layer number of plies, s_iPile head settlement position for i-th layer Move, Z is the depth in pile foundation residing for any point, C_siSoil layer viscosity for i-th layer, C_pFor pile foundation perimeter of section, when t is Between, k_siSoil layer coefficient of elasticity for i-th layer；

The continuum hypothesis of S2, the displacement according to soil layer and power, solve displacement impedance function at ground, that is,：

Wherein：For parmeter of Laplace transform,For soil thickness and the long ratio of stake, L is that stake is long；

Obtain displacement at pile top frequency responseAccording to Fourier transform property, try to achieve unit load displacement and ring Should, that is,：

Wherein：P is pile top load, F is displacement at pile top frequency response, and i ω is complex variable；

S3, the settling data table being calculated according to the formula in described step S1 and S2 under different loads value and time.

In such scheme, also include step S4 after described step S3, described settling data table is switched to data matrix, root Draw load-sedimentation-time graphics according to data matrix.

Implement the sedimentation analytic method based on pile behavior analysis of the present invention, have the advantages that：

1st, this method can provide the quantitative relationship between load-sedimentation-time, pre- using overload before the old and new's bridging connects The method of pressure accelerates the consolidation process of new bridge portion, is deformed with the posterior settlement reducing new bridge portion, and alleviating the additional of structure should Power, ensures that the normal of bridge uses and security performance.

2nd, it is firstly introduced time parameter in analysis by sedimentation, m- load deformation curve when establishing in infall process, In engineering in practice, can flexibly determine quantitative relationship between any two variables, concrete timing node is accurate to for settlement prediction, has It is beneficial to carry out real-time settlement Control and determine surcharge preloading technological parameter；

3rd, result of calculation can behave as three-dimensional function figure or program, after user is according to actual geological condition input data The comparative analysis between variable can intuitively be carried out, engineering actual carry out settlement prediction control when, can freely be selected according to engine request Take OK range and appropriate point, conveniently and efficiently instruct surcharge preloading construction technology.

Brief description

Below in conjunction with drawings and Examples, the invention will be further described, in accompanying drawing：

Fig. 1 is the flow chart of the sedimentation analytic method that the present invention is analyzed based on pile behavior；

Fig. 2 is load-sedimentation-time graphics.

Specific embodiment

In order to be more clearly understood to the technical characteristic of the present invention, purpose and effect, now comparison accompanying drawing describes in detail The specific embodiment of the present invention.

As shown in figure 1, the present invention is comprised the following steps based on the sedimentation analytic method that pile behavior is analyzed：

S1, to set up the micro unit equation of static equilibrium according to Load Transfer Method and shear displacement method as follows：

Wherein：E is pile foundation Young's modulus, and A is pile foundation sectional area, and i is the soil layer number of plies, i=1,2,3 ...；s_iFor i-th layer Pile head settlement displacement, Z is depth residing for any point in pile foundation, C_siSoil layer viscosity for i-th layer, C_pCut for pile foundation Face girth, t is the time, k_siSoil layer coefficient of elasticity for i-th layer；

The continuum hypothesis of S2, the displacement according to soil layer and power, solve displacement impedance function at ground, that is,：

Wherein：For parmeter of Laplace transform,For soil thickness and the long ratio of stake, L is that stake is long；

Obtain displacement at pile top frequency responseAccording to Fourier transform property, try to achieve unit load displacement and ring Should, that is,：

Wherein：P is pile top load, F is displacement at pile top frequency response, and i ω is the complex variable in Fourier transformation；

S3, calculated according to the formula in described step S1 and S2, substitute into load and temporal reference value, be calculated in certain level The sedimentation value of certain timing node under load, thus obtain the settling data table under different loads value and time.

S4, described settling data table is switched to data matrix, load-sedimentation-time graphics is drawn according to data matrix, As shown in Figure 2.Quantitative relationship between any two variables, root can be set up under conditions of a certain variable determines according to this figure Choose, according to requirement of engineering, appropriate area and the appropriate point meeting condition, surcharge preloading is instructed, makes the settlement request of new bridge Reach connection standard.

Above in conjunction with accompanying drawing, embodiments of the invention are described, but the invention is not limited in above-mentioned concrete Embodiment, above-mentioned specific embodiment is only schematically, rather than restricted, those of ordinary skill in the art Under the enlightenment of the present invention, in the case of without departing from present inventive concept and scope of the claimed protection, also can make a lot Form, these belong within the protection of the present invention.

Claims (2)

1. a kind of sedimentation analytic method based on pile behavior analysis is it is characterised in that comprise the following steps：

S1, to set up the micro unit equation of static equilibrium according to Load Transfer Method and shear displacement method as follows：

$EA\frac{{\∂}^2{s}_i}{\∂z^2}-c_{si}{C}_p\frac{\∂s_i}{\∂t}-k_{si}{C}_p{s}_i=0$

Wherein：E is pile foundation Young's modulus, and A is pile foundation sectional area, and i is the soil layer number of plies, s_iPile head settlement displacement for i-th layer, Z is Depth residing for any point in pile foundation, C_siSoil layer viscosity for i-th layer, C_pFor pile foundation perimeter of section, t is the time, k_si Soil layer coefficient of elasticity for i-th layer；

The continuum hypothesis of S2, the displacement according to soil layer and power, solve displacement impedance function at ground, that is,：

$Z\left(s\right)=-\frac{E_p{A}_p{\stackrel{\‾}{\mathrm{\λ}}}_n}{L}tan({\stackrel{\‾}{h}}_n{\stackrel{\‾}{\mathrm{\λ}}}_n-{\mathrm{\β}}_n)$

$tan\left({\mathrm{\β}}_n\right)=\frac{Z_{n-1}}{E_p{A}_p}\frac{L}{{\stackrel{\‾}{\mathrm{\λ}}}_n}$

Wherein：For parmeter of Laplace transform,For soil thickness and the long ratio of stake, L is that stake is long；

Obtain displacement at pile top frequency responseAccording to Fourier transform property, try to achieve unit load dynamic respond, I.e.：

$s\left(t\right)=\frac{P}{2\mathrm{\π}}\underset{-\∝}{\overset{\∝}{\∫}}\left(\frac{1}{i\mathrm{\ω}}\right)F\left(i\mathrm{\ω}\right)e^{i\mathrm{\ω}t}d\mathrm{\ω}+\frac{P}{2}F\left(0\right)$

Wherein：P is pile top load, F is displacement at pile top frequency response, and i ω is complex variable；

S3, the settling data table being calculated according to the formula in described step S1 and S2 under different loads value and time.

2. the sedimentation analytic method based on pile behavior analysis according to claim 1 it is characterised in that described step S3 it Also include step S4 afterwards, described settling data table is switched to data matrix, load-sedimentation-time three is drawn according to data matrix Dimension figure.