CN101793037B - Surface sedimentation rate method of rockfill roadbed high-fill structure - Google Patents

Abstract

The invention discloses a surface sedimentation rate method of a rockfill roadbed high-fill structure. The method comprises the following steps of: (1) determining a foundation consolidation parameter within a horizontal range of a dead-weight effect of the roadbed high-fill structure; (2) determining a creep parameter of the rockfill; (3) setting a roadbed surface sedimentation observation mark when the filling and the reinforcement of the rockfill are finished; (4) continuously observing the roadbed surface sedimentation deformation of a roadbed load prepressing maintenance stage; and (5) drawing a roadbed surface sedimentation time-history curve of different monitoring areas and calculating the time interval sedimentation rate of the roadbed load prepressing maintenance stage. The invention is simple, feasible, reasonable and effective.

Description

The rockfill roadbed high-fill structure surface sedimentation rate method

Technical field

Invention relates to the road primary surface sedimentation rate method that a kind of rockfill roadbed high-fill structure face settlement observation scheme, rate of settling analytical method and discrimination standard are determined, be called for short the rockfill roadbed high-fill structure surface sedimentation rate method, belong to technical field of civil engineering.

Background technology

Along with growing continuously and fast of China's economic construction, road base earth rock placement design adopts the overall plan in " cut the mountain and fill out paddy " and " cut into a mountain and fill out the sea " smooth place more and more, especially geographical environment is hilly ground, mountain area and coastal beach area, rockfill Dao Jigao embankment form of structure is widely used.

Rockfill fills Dao Jigao embankment structure, conventional base (foundation surface) is provided with settlement plate and successively takes over the method for carrying out continuous ground settlement observation, not only on the construction aspect, aggravate with the reciprocal effect of road base filling construction, even rockfill rams by force impact to reinforce the settlement plate extension bar destroyed and is difficult to avoid, cause the settlement plate severe attrition, can't finish expection settlement observation control target.In addition, on the aspect of technology, self compression creep of rockfill Dao Jigao embankment structure, becoming rule during to road base end face sedimentation also has a direct impact, only consider that the ground consolidation sedimentation evaluates groove top settlement after construction and control road face deck construction node, ignore the based structures creeping characteristic fully, unreasonable.

Therefore, how according to rockfill Dao Jigao embankment construction characteristic and architectural feature, seek the settlement monitoring scheme that rationally feasible groove district, road settlement after construction is estimated; Propose corresponding surface settlement rate analysis method, accurately analyze groove top settlement after construction; And set up rational rate of settling control criterion, and rationally control face deck construction node time, become the problem that presses for solution in the practice of enrockment height embankment reclamation work.

Summary of the invention

Technical problem:

The present invention seeks to provides a kind of rockfill roadbed high-fill structure face settlement observation scheme, rate of settling analytical method and discrimination standard definite road primary surface sedimentation rate method---rockfill roadbed high-fill structure surface sedimentation rate method at the defective that prior art exists.

Technical scheme:

The present invention adopts following technical scheme for achieving the above object:

Rockfill roadbed high-fill structure surface sedimentation rate method of the present invention is characterized in that comprising the steps:

1) determines the ground consolidation parameters;

2) determine the rockfill creep parameters;

3) rockfill fills and reinforces when finishing, and groove top surface settlement observation staff in time is set;

4) the road base is kept base load precompressed stage Continuous Observation sedimentation target sedimentation and deformation;

5) draw groove top, road, different monitored area sedimentation mark sedimentation time-history curves, calculate the rate of settling of the different periods of keeping the base load precompressed stage.

The ground consolidation rule adopts exponential model ${\stackrel{\‾}{U}}_t=1-\mathrm{\α}\·e^{-\mathrm{\β}\·t}$ Describe,

Be average degree of consolidation, t represents that α, β are consolidation parameters constantly, and e is the index truth of a matter, coefficient of consolidation C _vAdopt indoor undisturbed sample compression test, fill out the horizontal value of mean effort of base by height.

Described enrockment height embankment road primary surface sedimentation rate method is characterized in that rockfill creep employing exponential decay curve model ε (t)=a (1-e ^-ct), ε (t) is a t rockfill creep compliance constantly, a is a constant, adopts indoor rockfill reduced scale sample three all compression tests and compression creep test to determine.

Described rockfill roadbed high-fill structure surface sedimentation rate method is characterized in that the processing that homogenizes of different ground soil consolidation parameters, adopts different soil volume factor m _ViAnd osmotic coefficient k _ViSoil layer volume factor m after handling homogenizes _VmAnd osmotic coefficient k _Vm, press coefficient of consolidation definition $C_{\mathrm{vm}}=\frac{k_{\mathrm{vm}}}{m_{\mathrm{vm}}{\mathrm{\γ}}_w}$ Calculating is obtained, C _VmBe the coefficient of consolidation after the equalization processing, γ _wUnit weight for water.

The dynamic settling observing frequency is 15d～30d, and specifically comprehensively the precompressed cycle in base load precompressed stage is kept in base deadweight in road, and the size reasonable selection of surveying the rate of settling.

Different soil sample quantities, rockfill reduced scale sample quantities should meet existing related specifications requirement among the present invention.

The present invention is mainly used in the groove zone, and groove top surface sedimentation mark in road is arranged density, should meet existing related specifications requirement, and should take all factors into consideration groove district zones of different engineering characteristic and specifically lay.

Beneficial effect:

The present invention compares with existing sedimentation rate method, after only need loading and finish, the inventive method keeps the surface settlement detection of dynamic in base load precompressed stage, settlement observation point is laid simpler, the layout density adjustment is also convenient, simply, feasible and effective, tool has avoided loading the reciprocal effect of phase settlement observation and rockfill impact strengthening construction.The inventive method adopts ground consolidation and road base creep coupling analysis principle, combine the double action effect of ground compression concretion and road base rockfill compression creep, relatively only consider the foundation soil compression concretion, traditional rate of settling method of ignoring the creep of base rockfill is more reasonable, has more pervasive.

Description of drawings

Fig. 1: rockfill road base load time line.

Fig. 2: foundation soil sectional schematic diagram.

Fig. 3: typical section, keep base load precompressed stage surface settlement observation datagram.

Fig. 4: the inventive method flow chart.

The specific embodiment

Be elaborated below in conjunction with the technical scheme of accompanying drawing to invention:

As shown in Figure 4, rockfill Dao Jigao embankment engineering, road primary surface settlement after construction is made up of foundation soil consolidation settlement and the creep of Dao Ji rockfill, and road groove district end face settlement after construction is inevitable to be made up of creep stack behind the worker of consolidation settlement behind the worker of foundation soil and road base rockfill.

According to improving high wooden pretty Jie's method, the sedimentation rate method of traditional ground consolidation settlement can obtain a certain fixed moment t of ground, the ground consolidation rate of settling

With ground settlement after construction S _SDTRelation

$\frac{{\stackrel{\·}{S}}_{\mathrm{St}}}{\mathrm{\β}}=S_{\mathrm{SDT}}+{\mathrm{\χ}}_s---\left(1\right)$

In the formula, ${\mathrm{\χ}}_s=m_{\mathrm{vm}}h\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\stackrel{\·}{q}}_i\frac{\mathrm{\α}}{\mathrm{\β}}{e}^{-\mathrm{\β}{T}_D}(e^{\mathrm{\β}{T}_i}-e^{\mathrm{\β}{T}_{i-1}}),$ m _vBe the volume factor of different soil after homogenizing; H is a foundation soil thickness; It is the loading speed of i level load; α, β are consolidation parameters; T _DBe works design period; T _i, T _I-1Be respectively the starting point and the terminal time (starting at) of constant speed loadings at different levels from zero point.

Base creep rule in rockfill road adopts the exponential decay curve model, can be expressed as follows

ε _c(t)＝ε _cf(1-e ^-ct) (2)

In the formula, ε _c(t) be t rockfill creep compliance constantly; Constant a gets the final creep compliance ε of rockfill herein _CfC is the rockfill creep parameters, obtains by the rockfill rheological test.

Equally, introduce the pretty linear loading simulation method that is situated between of high wood, can obtain a certain moment t rockfill road base mean strain ε (t) and road primary surface compression creep speed

Expression formula

$\mathrm{\ϵ}\left(t\right)={\stackrel{\‾}{\mathrm{\ϵ}}}_{\mathrm{cf}}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\stackrel{\·}{q}}_i}{\mathrm{\Σ\Δp}}[(T_i-T_{i-1})-\frac{1}{c}{e}^{-\mathrm{ct}}(e^{c{T}_i}-e^{c{T}_{i-1}})]---\left(3\right)$

${\stackrel{\·}{S}}_{\mathrm{Gt}}={\stackrel{\‾}{\mathrm{\ϵ}}}_{\mathrm{cf}}H\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\stackrel{\·}{q}}_i}{\mathrm{\Σ\Δp}}\left[e^{-\mathrm{ct}}(e^{c{T}_i}-e^{c{T}_{i-1}})\right]---\left(4\right)$

In the formula, ∑ Δ p is the aggregate-value of loads at different levels; Final average creep in the rockfill filled height H

Can determine that according to road base selfweight stress triangle distribution characteristics, derivation is tried to achieve again according to rockfill laboratory triaxial compression test intensity index

In the formula, b, d are the rockfill creep parameters, obtain by creep test; C,

Be the rockfill intensity parameter; γ is a rockfill unit weight; H is a rockfill road base filled height.

According to rate of settling analysis principle, can obtain the primary surface creep rate

With compression creep amount S behind the road based structures worker _GDTRelation

$\frac{{\stackrel{\·}{S}}_{\mathrm{Gt}}}{c}=S_{\mathrm{GDT}}+{\mathrm{\χ}}_G---\left(6\right)$

In the formula, ${\mathrm{\χ}}_G=S_{\mathrm{GcfH}}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\stackrel{\·}{q}}_i}{\mathrm{\Σ\Δp}}\frac{1}{c}{e}^{-c{T}_D}(e^{c{T}_i}-e^{c{T}_{i-1}}),$ S _GcfHBe final deformation of creep amount in the rockfill filled height H; All the other parameter meanings as previously mentioned.

Road primary surface sedimentation rate method adopts the rockfill creep rate to analyze with the ground consolidation rate of settling and analyzes coupling process, i.e. basis

${\stackrel{\·}{S}}_t=S_{\mathrm{Scf}}\·{\stackrel{\·}{U}}_{\mathrm{St}}+S_{\mathrm{Gcf}}\·{\stackrel{\·}{U}}_{\mathrm{Gt}}={\stackrel{\·}{S}}_{\mathrm{St}}+{\stackrel{\·}{S}}_{\mathrm{Gt}}---\left(7\right)$

In the formula, S _Scf,

The degree of consolidation when being respectively final consolidation deformation amount of ground and t; S _Gcf,

Rheidity rheosphere when being respectively final deformation of creep amount of rockfill and t.

With above-mentioned expression formula (1) and expression formula (6), the above-mentioned expression formula of substitution (7) can obtain after the arrangement

$\frac{{\stackrel{\·}{S}}_t}{\mathrm{\λ}}=S_{\mathrm{DT}}+\mathrm{\χ}---\left(8\right)$

In the formula,

Be the road base rate of settling; S _DTBe road base settlement after construction; χ=χ _S+ χ _G, χ wherein _S, χ _GMeaning is stated as previously mentioned; $\mathrm{\λ}=\mathrm{\β}\frac{c+c{\mathrm{\ξ}}_t}{c+\mathrm{\β}{\mathrm{\ξ}}_t},$ ${\mathrm{\ξ}}_t=\frac{{\stackrel{\·}{S}}_{\mathrm{Gt}}}{{\stackrel{\·}{S}}_{\mathrm{St}}}=\frac{S_{\mathrm{Gcf}}}{S_c}\frac{e^{(\mathrm{\β}-c)t}}{\mathrm{\α}}\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\stackrel{\·}{q}}_i(e^{c{T}_i}-e^{c{T}_{i-1}})}{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\stackrel{\·}{q}}_i(e^{\mathrm{\β}{T}_i}-e^{\mathrm{\β}{T}_{i-1}})},$ S wherein _cBe the ground consolidation sedimentation, all the other each parameter meanings as previously mentioned.

Adopt above-mentioned expression formula (8), keep the sedimentation time-histories rule that the surface settlement observation in base load precompressed stage obtains after can directly utilizing rockfill Dao Jigao embankment structure to fill to finish, i.e. the surface settlement rate

Index, the settlement after construction of assay road primary surface (being mainly used in the groove top), control groove district, road road surface layer structure engineering time node.

Rockfill roadbed high-fill structure surface sedimentation rate method application flow is: 1. preparation, the test that comprises the ground consolidation parameter determines and tests such as rockfill intensity, creep parameters are determined, and the determining of design prospecting indexs such as rockfill road base height, foundation soil thickness; 2. standard analysis, in above-mentioned rockfill roadbed high-fill structure surface sedimentation rate method, surface settlement rate analysis principle and method, and the calculating parameter of preparation stage acquisition, by groove district, the road settlement after construction control criterion of designing requirement, analyze and obtain corresponding groove district, road end face rate of settling control criterion; 3. test phase, comprise rockfill Dao Jigao embankment structure fill finish after, groove district, road end face sedimentation mark is arranged and is buried underground, and carries out the dynamic monitoring of surface settlement mark by the design code test frequency, obtains to keep groove district, the road end face sedimentation time-histories rule achievement curve in base load precompressed stage; 4. estimate control, according to rockfill Dao Jigao embankment structure actual measurement surface settlement rate and respective sustain road base load precompressed cycle, the actual measurement rate of settling is less than above-mentioned standard, and the corresponding precompressed phase more in short-term, can judge that groove district settlement after construction less than the design control criterion, can launch the construction of face deck in good time; Otherwise the actual measurement rate of settling is greater than above-mentioned standard, and the corresponding precompressed phase is when longer, can judge that groove district settlement after construction is still greater than the design control criterion, and need proceed the observation of precompressed and dynamic settling,, can carry out the construction of face deck until satisfying rate of settling standard.

When the rockfill roadbed high-fill structure surface sedimentation rate method is applied to the settlement after construction evaluation of groove district with construction control, three outstanding features are arranged: 1. adopt the settlement observation scheme in base load precompressed stage of keeping, need not impact and carry out settlement observation in the strengthening construction process, avoid and the serious reciprocal effect of impact strengthening construction at rockfill; 2. adopt primary surface settlement observation scheme, take into full account the combined effect of ground compression concretion and the base rockfill compression creep of high embankment road, groove district, road settlement after construction assay and road face deck engineering time node control are more reasonable, and do not exist rockfill to impact reinforcing destroys sternness to the conventional base settlement plate problem; 3. the analysis of surface settlement speed control criterion is determined, taken into full account the creeping characteristic of concrete engineering foundation soil consolidation characteristic and enrockment height embankment structure, in traditional relatively ground sedimentation rate method, do not consider the whole fixed feature of ground, rate of settling control criterion is as the method for an empirical definite value, have more specific aim, and more reasonable.

The rockfill roadbed high-fill structure surface sedimentation rate method is applied to groove district settlement after construction and estimates and the control of road surface construction timing node, does not comprise that rockfill fills the strength stability control in the process.General rockfill road base is large tracts of land and fills, and intensity stabilization control depends primarily on the whole sliding stability of side slope, and the settlement monitoring in the inner filling construction process in place is meaningless to intensity stabilization control.Maybe need to carry out the zone of local stability monitoring for the engineering that needs to carry out stability monitoring really, suggestion adopts side slope toe deep horizontal displacement or super quiet hole to press the stability monitoring technology.Simultaneously, should strengthen the analysis of rockfill side slope monolithic stability, the whole sliding stability of rational evaluation loading procedure road base side slope in the design stage.Generally speaking, the intensity stabilization settlement observation of filling loading phase cancellation large tracts of land dumping area totally is rational.

Embodiment

Rely on certain rockfill road base reclamation work, residual settlement amount≤8cm behind road groove district's designing requirement worker.Choose a certain clay distribution typical section, this section face rockfill road base fills loading level and loading and time relationship, referring to Fig. 1; The foundation soil character of typical section is referring to Fig. 2.

Utilize aforementioned analytical method, this typical section is analyzed, calculating parameter is referring to table 1, and result of calculation is referring to table 2.As can be seen, the crude sedimentation soil thickness is 8.0m, and rate of settling standard is 8mm/ during the month, keeps the precompressed of base load after two months, and road groove district settlement after construction can satisfy 8cm design control criterion.Rely on engineering crude sedimentation soil thickness to be generally less than 8.0m, and it is shorter stable period to analyze the precompressed that obtains, it is rational adopting 8mm/ month rate of settling standard.Typical section is kept base load precompressed stage surface settlement observation data, referring to Fig. 3.As can be seen, keep base load precompressed two months, each observation point has all satisfied corresponding rate of settling standard, can select a good opportunity and launch road face deck construction.

Simultaneously, analysis results shows, at the design control criterion of road groove district settlement after construction 8cm, and different foundation soil thickness, corresponding rate of settling standard is not quite similar.When supposition soil thickness when being 12m, groove district, corresponding road rate of settling standard is reduced to the 5mm/ month, just can reach the design control criterion of groove district settlement after construction 8cm, and it is longer to reach precompressed cycle of this rate of settling standard, and corresponding settlement after construction is bigger.Therefore, obtain corresponding rate of settling standard at concrete fractograph analysis, and comprehensive precompressed cycle length, evaluate the method for groove district settlement after construction, rate of settling standard is made as the method for experience definite value in traditional relatively sedimentation rate method, and is more reasonable.

By above-mentioned instance analysis, can think that rockfill roadbed high-fill structure surface sedimentation rate method is rationally effective, and simple possible.

Table 1

Table 2

Claims (5)

1. a rockfill roadbed high-fill structure surface sedimentation rate method is characterized in that comprising the steps:

1) determines ground consolidation parameter in the Dao Jigao embankment dead load load action horizontal extent;

2) determine the creep parameters of rockfill;

3) rockfill fills to reinforce the primary surface settlement observation staff is set when finishing;

4) Continuous Observation is kept the road primary surface sedimentation and deformation in base load precompressed stage;

5) draw road, different monitored area primary surface sedimentation time-history curves, calculate and keep the different period rates of settling in base load precompressed stage.

2. enrockment height embankment according to claim 1 road primary surface sedimentation rate method is characterized in that the ground consolidation rule adopts exponential model ${\stackrel{\‾}{U}}_t=1-\mathrm{\α}\·e^{-\mathrm{\β}\·t}$ Describe,

Be average degree of consolidation, t represents that α, β are consolidation parameters constantly, and e is the index truth of a matter, coefficient of consolidation C _vAdopt indoor undisturbed sample compression test, fill out the horizontal value of mean effort of base by height.

3. enrockment height embankment according to claim 1 road primary surface sedimentation rate method is characterized in that rockfill creep employing exponential decay curve model ε (t)=a (1-e ^-ct), ε (t) is a t rockfill creep compliance constantly, a is a constant, adopts indoor rockfill reduced scale sample three all compression tests and compression creep test to determine.

4. rockfill roadbed high-fill structure surface sedimentation rate method according to claim 1 and 2 is characterized in that the processing that homogenizes of different ground soil consolidation parameters, adopts different soil volume factor m _ViAnd osmotic coefficient k _ViSoil layer volume factor m after handling homogenizes _VmAnd osmotic coefficient k _Vm, press coefficient of consolidation definition $C_{\mathrm{vm}}=\frac{k_{\mathrm{vm}}}{m_{\mathrm{vm}}{\mathrm{\γ}}_w}$ Calculating is obtained, C _VmBe the coefficient of consolidation after the equalization processing, γ _wUnit weight for water.

5. rockfill according to claim 1 fills Dao Jigao embankment body structure surface sedimentation rate method, it is characterized in that the dynamic settling observing frequency is 15d～30d.

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