CN104866664A - Method for predicting construction difficulty of water seepage prevention curtain-grouting - Google Patents

Abstract

The present invention discloses a method for predicting construction difficulty of water seepage prevention curtain-grouting, wherein the method includes the following steps: performing construction for the water seepage prevention curtain-grouting by using a construction equipment and combing with geologic conditions in a construction field; performing layer division and classification to each factor cooperative with analyzing each factor affecting construction difficulty, and forming grading evaluation criteria of each construction difficulty with respect to each factor; and analyzing each factor by using the analytic hierarchy process (AHP) to obtain index weight of each factor affecting construction difficulty. The appraising system according to the present invention is concise and convenient, and has a simple operation. The construction difficulty is predicted in advance according to the factor affecting the construction difficulty of the water seepage prevention curtain-grouting, which can evaluate a project in detail, and the result is more rational and sound; the factor having a high level of risk can be circumvented or adjusted in advance, thereby achieving a fundamental purpose of reducing the duration, saving the cost, and reducing the construction difficulty.

Description

A kind of Impermeable underground wall curtain body construction difficulty Forecasting Methodology

Technical field

The present invention relates to geotechnical engineering design and construction field, particularly relating to is a kind ofly carry out advanced prediction based on AHP-TOPSIS scoring model, evaluate area of bordering on the sea containing the method for coral reef chip stratum water-stop curtain body construction complexity.

Background technology

The regional rock deep foundation pit construction difficulty that enters that borders on the sea is the focus that foundation construction personnel study, pay close attention to always.Wherein, construction site environment is changeable, complex geologic conditions, and construction treating methods difference that is various and preparation of construction type selecting all produces larger impact by difficulty of construction.But border on the sea less into rock deep foundation pit construction case, construction experience that can be for reference is also few, lacks the various factor analysis affecting construction quality.Therefore, it may be necessary theoretical research and case history application, analyze further, sum up and border on the sea into the construction quality influence factor of rock deep basal pit Impermeable underground wall curtain body, thus obtain field construction difficulty defining method more accurately.

Existing construction site difficulty evaluation method is mainly divided into geological analysis predicted method and the large class of geophysics predicted method two.Geological analysis predicted method mainly comprises advanced levels, vertically holes, engineering geological survey method etc.; Geophysics predicted method comprises sonic test, infrared acquisition, wave velocity method and Electromagnetic Wave Method etc.Advanced levels, vertical boring are one of advanced prediction most effectual ways, but also Shortcomings part: better to the geologic structure face value of forecasting of Vertical dimension, and the forecast of horizontal direction structural plane is poor, need take the longer construction operation time, costly; Engineering geological survey method is the method used in geologic prediction the earliest, the method be by inquiry with analysis earth's surface engineering geological condition, understand the geological structure characteristic in location residing for engineering, infer geological condition herein according to the engineering project of similar vicinity; Sonic test, infrared acquisition, wave velocity method and Electromagnetic Wave Method etc. are all utilize geophysical prospecting method to carry out prospecting prediction to construction site, have certain reference value.But it can only know the information on stratum itself briefly, thus evaluate the influence degree of stratum for construction itself, the impact for work progress such as working measure and plant equipment cannot be considered.

Summary of the invention

The object of the invention is to border on the sea containing a design and construction difficult problem for coral reef chip stratum Impermeable underground wall curtain body for solving better, a kind of Impermeable underground wall curtain body construction difficulty Forecasting Methodology is proposed, it can carry out comprehensive anticipation to area of bordering on the sea containing coral reef soil layer difficulty of construction in advance according to field engineering geologic condition, the factor such as preparation of construction intending taking measures and intend to adopt, for the selection of construction method and preparation of construction provides certain reference, evade adverse risk in advance, optimum selecting, thus carry out site operation more fast, efficiently, economically.

For solving the problems of the technologies described above, the invention provides following technical scheme:

A kind of Impermeable underground wall curtain body construction difficulty Forecasting Methodology, comprises the steps:

Step 1, preparation of construction is utilized to carry out an Impermeable underground wall curtain body construction in conjunction with geologic condition on construction ground;

Step 2, the comprehensive each factor analyzing Effect Field ground difficulty of construction, carry out distinguishing hierarchy to described each factor and sort out, forming each construction difficulty or ease grade evaluation criterion for every class factor;

Step 3, utilize APH analytical hierarchy process analyze described each factor, obtain the index weights that each factor affects for difficulty of construction;

Step 4, in conjunction with TOPSIS similarity to ideal solution ranking method, respectively risk class division is carried out to the influence factor of same level according to above-mentioned difficulty of construction grade evaluation criterion, determine the influential effect of each level factor.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, according to the influential effect of each level factor, adjust arrangement and method for construction and/or the preparation of construction of next block Impermeable underground wall curtain body in time, evade adverse risk in advance.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, the described each factor affecting place difficulty of construction is divided into geologic condition, preparation of construction and working measure three class.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, described geologic condition comprises the thickness of overburden layer, the homogeneity of upper overburden layer, the fluctuating quantity of bedrock surface, Coral Reef Rock distribution situation and severely-weathered layer distribution situation; Described preparation of construction comprises mixing pile stake machine type, jet grouting pile driving machine, inspecting hole, draws drilling machine and water power standby condition; And working measure comprises examination pore-forming, inspecting hole, draws hole and lower pipe.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, described construction site is positioned at borders on the sea containing Coral Reef Rock area, geologic structure is from top to bottom followed successively by: containing the soil layer of Coral Reef Rock rock mass, severely-weathered layer and middle waste mantle, and described Impermeable underground wall curtain body adopts the combined enclosure form of three axes agitating pile and high-pressure rotary jet grouting pile on vertical section.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, the construction procedure of described Impermeable underground wall curtain body comprises:

Step 11, carries out examination pile to construction site, tentatively determines the construction parameter of three axes agitating pile and high-pressure rotary jet grouting pile;

Step 12, adopts rig to carry out inspecting hole, verifies the bedrock surface buried depth situation containing the Coral Reef Rock depth of stratum in the soil layer of Coral Reef Rock, severely-weathered layer thickness and middle waste mantle;

Step 13, for containing the soil layer of Coral Reef Rock and severely-weathered stratum, adopt single cover to make three axes agitating pile stake machine and construct, three axes agitating pile injection is to the bedrock surface above 1.0-1.5 rice degree of depth;

Step 14, carries out drawing hole, draws more than 1m under hole to bedrock surface after three axes agitating pile has been constructed, can whole hole after guaranteeing to enter basement rock projected depth, and pore-forming aperture is not less than 130mm, and perpendicularity deviation is not more than 1/200, and the biased difference in hole is not more than 20mm;

Step 15, it is complete with down tube to draw hole, and adopt pvc pipe, by pvc pipe back cover, interior mud grouting, transfers more than 1m to bedrock surface from drawing hole;

Step 16, utilize jet grouting pile driving machine construction high-pressure rotary jet grouting pile, enter bedrock surface more than 1.0 meters under high-pressure rotary jet grouting pile, high-pressure rotary jet grouting pile and three axes agitating pile effectively overlap more than 1.0 meters.

Optionally, in above-mentioned Impermeable underground wall curtain body construction difficulty Forecasting Methodology, in step 15, if the sludge of precipitation is thicker at the bottom of hole, necessary clear hole deslagging, guarantees that pvc pipe enters below bedrock surface more than 1.0 meters.

From above disclosed technical scheme, compared with prior art, beneficial effect of the present invention is as follows:

(1) the present invention is according to utilizing preparation of construction to carry out the situation of an Impermeable underground wall curtain body construction in conjunction with geologic condition on construction ground, the first comprehensive principal element analyzing Effect Field ground difficulty of construction, and classification that above-mentioned factor is summarized, AHP analytical hierarchy process is utilized to obtain the weighing factor of each factor, finally in conjunction with TOPSIS method, grade judgement is carried out to each factor, thus the difficulty of construction risk class of each factor can be known more concisely, for the factor that risk class is higher, can process in advance when next Impermeable underground wall curtain body process, carry out in advance evading or adjusting, thus reach the minimizing duration, cost-saving, reduce the basic goal of difficulty of construction.

(2) the present invention will affect the geologic condition of difficulty of construction, preparation of construction and the interrelated and comprehensive analysis of working measure, and can do one to some engineerings all sidedly and evaluate in detail, result has more rationality and integrity.

(3) the present invention can so that realize foundation pit waterproof curtain design and construction cost and the estimating of construction period.

(4) difficulty of construction appraisement system of the present invention succinctly facilitates, workable, to the South Sea border on the sea containing coral reef chip stratum construction evaluation have better applicability.

Accompanying drawing explanation

Fig. 1 is the concrete construction flow chart of Impermeable underground wall curtain body;

Fig. 2 is the hierarchy Model setting up difficulty of construction prediction by AHP method according to geologic condition, preparation of construction and working measure.

Embodiment

Below in conjunction with the drawings and specific embodiments, the Impermeable underground wall curtain body construction difficulty Forecasting Methodology that the present invention proposes is described in further detail.According to the following describes and claims, advantages and features of the invention will be clearer.It should be noted that, accompanying drawing all adopts the form that simplifies very much and all uses non-ratio accurately, only in order to object that is convenient, the aid illustration embodiment of the present invention lucidly.

Present embodiment discloses a kind of Impermeable underground wall curtain body construction difficulty Forecasting Methodology, this method is successfully applied to the South Sea and borders on the sea containing in certain engineering in Coral Reef Rock area, the geologic structure bordered on the sea containing Coral Reef Rock area in the South Sea is from top to bottom followed successively by: containing the soil layer of Coral Reef Rock, severely-weathered layer and middle waste mantle, described Impermeable underground wall curtain body adopts the combined enclosure form of three axes agitating pile and high-pressure rotary jet grouting pile on vertical section.Described Impermeable underground wall curtain body construction difficulty Forecasting Methodology specifically comprises the steps:

1, preparation of construction is utilized to carry out an Impermeable underground wall curtain body construction in conjunction with geologic condition on construction ground.

The construction site of the present embodiment is positioned at borders on the sea containing Coral Reef Rock area, and therefore, on vertical section, the preferential combined enclosure pattern that adopts carries out water-stop curtain design.Foundation pit waterproof curtain is designed to: on vertical section, adopt combined enclosure pattern, that is: for containing the soil layer of Coral Reef Rock and severely-weathered layer, the three axes agitating pile adopting single cover to beat Φ 850@1200 is constructed, three axes agitating pile injection is to bedrock surface 1.0 meters of degree of depth, then on mixing pile, adopt the concentric preexisting hole of conventional drill to enter more than 1.0 meters, basement rock, to construct again high-pressure rotary jet grouting pile, make water seepage prevention fender body enter the relatively fluid-tight middle waste mantle of basement rock.Enter 1.0 meters, basement rock under high-pressure rotary jet grouting pile, upper and three axes agitating pile effectively overlaps 1.0 meters.

Under the prerequisite that geologic condition and preparation of construction have been selected, in advance to construction site examination pore-forming, briefly should understand construction condition, determine design parameter, then adopt inspecting hole, draw the measure such as hole and lower pipe and carry out construction performance prediction.The concrete construction technology process of described Impermeable underground wall curtain body is as shown in Figure 1:

(1) step 11, examination pile, namely carries out examination pile to construction site, tentatively determines the construction parameter of three axes agitating pile and high-pressure rotary jet grouting pile

Before design and construction, tackle construction site carry out examination bore forming, determine the design construction parameter of three axes agitating pile and high-pressure rotary jet grouting pile.

(2) step 12, inspecting hole, namely adopts rig to carry out inspecting hole, verifies the upper overburden layer of more than bedrock surface namely containing the bedrock surface buried depth situation of Coral Reef Rock depth of stratum, severely-weathered layer thickness and the middle waste mantle in the soil layer of Coral Reef Rock;

Because engineering geological condition is complicated, Coral Reef Rock rock stratum skewness, bedrock surface fluctuations is larger, in order to verify the situations such as Coral Reef Rock depth of stratum, severely-weathered layer thickness, bedrock surface buried depth of top surface, G-150 type rig is first adopted to carry out inspecting hole, inspecting hole is to bedrock surface, and the spacing of inspecting hole must be equal with the three axes agitating pile machine centre distance of this project construction usage, and inspecting hole spacing is 1.2m.Record Coral Reef Rock depth of stratum, severely-weathered layer thickness, bedrock surface absolute altitude, to instruct three axes agitating pile mechanical execution.

Three are had to the object that position, every secondary mixing pile place rig carries out inspecting hole: 1. identify whether or not Coral Reef Rock distribution and depth of stratum thereof before construction three axes agitating pile, when distributing without Coral Reef Rock, employing normal triaxial mixing pile construction; When there being Coral Reef Rock to distribute, but its in the axial direction length be less than 2.0 meters and its thickness is less than 1.5 meters time, three axes agitating pile of can directly constructing, it should be noted that when injection three axes agitating pile adopt corresponding construction parameter; When its in the axial direction length be greater than 2 meters or its thickness be greater than 1.5 meters time, the heavy caliber reciprocating drill rig in 1.2 meters, a footpath should be adopted first to carry out punching process, behind complete broken Coral Reef Rock rock stratum, backfill sand again and compacting, three axes agitating pile of then constructing.2. severely-weathered layer thickness is determined, because severely-weathered layer thickness is uneven, and soil layer disproportionately graded, the more difficult control of three axes agitating pile construction quality, according to the severely-weathered layer thickness that inspecting hole obtains, and the severely-weathered level situation of joining is recorded in inspecting hole table, construction parameter is advised.3. determine bedrock surface buried depth of top surface, below, in work progress, mixing pile stops beating 1 ~ 1.5m more than bedrock surface, in order to avoid three axes agitating pile stake machine stirring-head is encountered basement rock and damages a machine, occurs embracing the problems such as brill, bit freezing.

(3) step 13, three axes agitating pile pile driving construction

For containing the soil layer of Coral Reef Rock and severely-weathered stratum, the three axes agitating pile stake machine adopting single cover to beat Φ 850@1200 is constructed, and three axes agitating pile injection is to the bedrock surface above 1.0-1.5 rice degree of depth.

(4) step 14, draws hole

Carry out drawing hole and high-pressure rotary jet grouting pile preexisting hole, 1m under preexisting hole to bedrock surface after three axes agitating pile has been constructed, can whole hole after guaranteeing to enter basement rock projected depth.Pore-forming aperture is not less than 130mm, and perpendicularity deviation is not more than 1/200, and the biased difference in hole is not more than 20mm.

(5) step 15, lower pipe

Draw hole complete after, transfer pvc pipe, adopt pvc pipe, tubing intensity is 1.0-1.5Mpa, pipe external diameter is the pvc pipe of 120mm, by the blanking of the preexisting hole degree of depth.By pvc pipe back cover, interior mud grouting, transfers 1m to bedrock surface from drawing hole, if the sludge of precipitation is thicker at the bottom of hole, necessary clear hole deslagging, guarantees that pvc pipe enters below bedrock surface 1.0 meters.

(6) step 16, Construction of High Pressure Jet Grouting Pile

Utilize jet grouting pile driving machine construction high-pressure rotary jet grouting pile, (making water seepage prevention fender body entirety enter this velatively waterproof layer of middle waste mantle), enter bedrock surface more than 1.0 meters under high-pressure rotary jet grouting pile, high-pressure rotary jet grouting pile and three axes agitating pile effectively overlap more than 1.0 meters.

When high-pressure rotary jet grouting pile is constructed for the first time, with mixing pile concentric axis by 0.6 meter of spacing preexisting hole, injection high-pressure rotary jet grouting pile; Then, as found after testing, to there is pile quality bad, when there is breakthrough again at former construction axial offset by different spacing injection high-pressure rotary jet grouting pile to reinforce pile body.Concrete construction process is illustrated in fig. 1 shown below:

2, the comprehensive each factor analyzing Effect Field ground difficulty of construction, carries out distinguishing hierarchy to described each factor and sorts out, forming each construction difficulty or ease grade evaluation criterion for every class factor.

By researching and analysing step 1, the each factor affecting place difficulty of construction is divided into geologic condition, preparation of construction and working measure three class, wherein, described geologic condition comprises the thickness of overburden layer, the homogeneity of upper overburden layer, the fluctuating quantity of bedrock surface, Coral Reef Rock distribution situation and severely-weathered layer distribution situation; Described preparation of construction comprises mixing pile stake machine type, jet grouting pile driving machine, inspecting hole, draws drilling machine and water power standby condition; And working measure comprises examination pore-forming, inspecting hole, draws hole and lower pipe.Difficulty of construction is divided Three Estate according to numerical values recited by geologic condition, preparation of construction and working measure three influence factors, is respectively more easily, more difficult, be difficult to.Construction difficulty or ease grade evaluation criterion is as shown in following table 1 to table 3, wherein difficulty of construction grade evaluation criterion one, two, three difference corresponding geologic condition, preparation of construction and working measure three class influence factor, wherein, Geological condition data N to be evaluated is the condition of construction gained according to step 1.

Table 1 difficulty of construction grade evaluation criterion one

Table 2 difficulty of construction grade evaluation criterion two

Table 3 difficulty of construction grade evaluation criterion three

Grade of difficulty	Examination pile	Inspecting hole	Draw hole	Lower pipe
					N1 (easier)	7	7	7	7
N2 (more difficult)	3	3	3	3
					N3 (being difficult to)	1	1	1	1
Working measure data N to be evaluated	8.5	8.2	7.5	7.4

3, utilize APH analytical hierarchy process to analyze described each factor, obtain the index weights that each factor affects for difficulty of construction.

(1) scale is compared

According to the scale that compares between two with judge principle, the index of correlation of employing paried comparison method to same level compares assignment, and scoring criteria is as shown in table 4 below.Standard value 2,4,6,8 represent that the importance of phase specific factor is between 2 adjacent ranks, if W _ij=r _i/ r _j, then 1/W _ij=r _j/ r _i,wherein, r _ibe i-th factor value, r _jfor a jth factor value.

Table 4 index significance level classification scoring criteria

Standard value	Definition	Explanation
			1	Of equal importance	Factor ri is identical with rj importance
3	Important a little	Factor ri and rj importance slightly high
			5	Important	Factor ri and rj importance higher
7	Obviously important	Factor ri and rj importance obviously high
			9	Definitely important	Factor ri and rj importance definitely high

(2) Judgement Matricies

If judgment matrix is R, due to every one deck index factor all with each index factor of adjacent last layer for object of reference, therefore can Judgement Matricies R:r by comparing Scale Method between two _ijrepresent r _i/ r _j, i.e. i-th factor value and a jth factor value importance comparison, alternatively, i-th index factor and a jth index factor importance comparison)

R is positive definite reciprocal matrix, for positive definite reciprocal matrix, and its eigenvalue of maximum λ _maxto exist and unique.Make a _ij=W _i/ W _j, the weight shared by certain factor of judgment matrix R and characteristic vector W _iwith eigenvalue of maximum λ _maxcomputing formula as follows:

${\tilde{W}}_{\mathrm{ij}}=a_{\mathrm{ij}}/\underset{j=1}{\overset{n}{\mathrm{\Σ}}}{a}_{\mathrm{ij}}$

$W_i=\sqrt[n]{\underset{j=1}{\overset{n}{\mathrm{\Π}}}{\tilde{W}}_{\mathrm{ij}}}/\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\sqrt[n]{\underset{j=`}{\overset{n}{\mathrm{\Π}}}{\tilde{W}}_{\mathrm{ij}}}$

${\mathrm{\λ}}_{\max }=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\left(\mathrm{RW}\right)}_i}{{\mathrm{nW}}_i}$

(3) consistency check and calculating weight vectors

Whether, due to complicacy and the subjective one-sidedness of systems engineering, there is error in judgment matrix unavoidably, reasonable for solving weight allocation, needs to carry out consistency check to judgment matrix.The formula of definition consistency check is:

$\mathrm{CR}=\frac{\mathrm{CI}}{\mathrm{RI}}=\frac{{\mathrm{\λ}}_{\max }-n}{(n-1)\mathrm{RI}}$

In formula: n is the exponent number of paired comparative factor, CI is consistency check index, and RI is Aver-age Random Consistency Index, gets different values according to the exponent number of paired comparative factor, and value standard is as shown in table 5 below.Whether meet the demands (i.e. CR<0.1) according to the consistance of result of calculation judgment matrix, otherwise need adjustment weight to make judgment matrix meet consistency check.

Table 5 Aver-age Random Consistency Index scoring criteria

Exponent number	RI
		1	0.00
2	0.00
		3	0.58
4	0.90
		5	1.12
6	1.24
		7	1.32
8	1.41
		9	1.45
10	1.49

If judgment matrix meets consistency check, illustrate that the structure of multi-level judgment matrix meets mathematical logic, the calculating of weights can be carried out according to this matrix, try to achieve weight vector.

In the present embodiment, set up the hierarchy Model of difficulty of construction foundation by AHP method according to geologic condition, preparation of construction and working measure, as shown in Figure 2, importance degree evaluation is carried out to index, the judgment matrix of construction rules layer P and each factor of indicator layer R.A-P, P1-R, P2-R, P3-R judgment matrix is respectively as shown in table 6 ~ 9.

Table 6 A-P judgment matrix

A-P	P 1	P 2	P 3
				P 1	1	3	3
P 2	1/3	1	2
				P 3	1/3	1/2	1

Table 7 P ₁-R judgment matrix

P 1-R	r 1	r 2	r 3	r 4	r 5
						r 1	1	1/3	1/2	1/5	1/4
r 2	3	1	5	1/2	3
						r 3	2	1/5	1	1/4	1/5
r 4	5	2	4	1	2
						r 5	4	1/3	5	1/2	1

Table 8 P ₂-R judgment matrix

P 2-R	r 6	r 7	r 8	r 9
					r 6	1	1/3	1/2	1/3
r 7	3	1	3	5

r 8	2	1/3	1	4
					r 9	1/3	1/5	1/4	1

Table 9 P ₃-R judgment matrix

P 3-R	r 10	r 11	r 12	r 13
					r 10	1	1/3	1/4	1/4
r 11	3	1	1/2	1/3
					r 12	4	2	1	2
r 13	4	3	1/2	1

Finally, the difficulty of construction prediction weight shown in table 10 is obtained.

Table 10 total hierarchial sorting result

4, in conjunction with TOPSIS similarity to ideal solution ranking method, respectively risk class division is carried out to the influence factor of same level according to above-mentioned difficulty of construction grade evaluation criterion, determine the influential effect of each level factor.Its principle is as follows:

(1) initial Judgement Matrix

If scheme collection P={P ₁, P ₂..., P _m, each scheme judging quota collection r={r ₁, r ₂..., r _n, judging quota r _ijrepresent a jth judging quota of i-th scheme, wherein i ∈ [1, m], j ∈ [1, n], initial Judgement Matrix can be expressed as:

(2) standardization decision matrix

Judging quota can be divided into expendable index and rentability index, and for expendable index, be worth the smaller the better, for rentability index, value is the bigger the better.Because each judging quota has different dimensions and dimensional unit, do not possess comparable degree, in order to eliminate the incommensurability of index, needing that dimension one is carried out to judging quota and changing process.For standardization decision matrix B=(b _ij) _{m × n}, computing formula is:

For rentability index, have

$b_{\mathrm{ij}}=\frac{r_{\mathrm{ij}}-\underset{j}{\mathrm{mi\; n}\left(r_{\mathrm{ij}}\right)}}{\underset{j}{\max \left(r_{\mathrm{ij}}\right)}-\underset{j}{\min \left(r_{\mathrm{ij}}\right)}}$

For expendable index, have

$b_{\mathrm{ij}}=\frac{\underset{j}{\min \left(r_{\mathrm{ij}}\right)}-r_{\mathrm{ij}}}{\underset{j}{\max \left(r_{\mathrm{ij}}\right)}-\underset{j}{\min \left(r_{\mathrm{ij}}\right)}}$

Wherein: for jth row minimum value, for jth row maximal value.

(3) weighting standard decision matrix

The indicator layer total hierarchial sorting weights W that the column vector of matrix B and AHP method are determined _nbe multiplied, weighting standard decision matrix R can be obtained ₁for

(4) approach degree analysis

Rentability index set J ₁positive ideal solution be the maximal value of row vector, minus ideal result is the minimum value of row vector, expendable index set J ₂value in contrast, can be expressed as

$\left.\begin{array}{c}{R_1}^{+}=\{\left(\underset{n}{\max }{w}_n{b}_{\mathrm{mn}}\right|{m\&Element;J}_1),\left(\underset{n}{\min }{w}_n{b}_{\mathrm{mn}}\right|m\&Element;J_2)\}\\ {R_1}^{-}=\{\left(\underset{n}{\min }{w}_n{b}_{\mathrm{mn}}\right|m\&Element;J_1),\left(\underset{n}{\max }{w}_n{b}_{\mathrm{mn}}\right|m\&Element;J_2)\}\end{array}\right\}$

In formula: R ₁ ⁺with R ₁ ^-be respectively positive ideal solution and minus ideal result.The distance passing judgment on object and ideal solution is

$\left.\begin{array}{c}{D}_i^{+}=\sqrt{\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{(r_{\mathrm{ij}}-r_j^{+})}^2}\\ D_i^{-}=\sqrt{\underset{j=1}{\overset{n}{\mathrm{\&Sigma;}}}{(r_{\mathrm{ij}}-r_j^{-})}^2}\end{array}\right\}$

In formula: D _i ⁺, D _i ^-be respectively the distance passing judgment on object and positive ideal solution and minus ideal result; r _i ⁺, r _i ^-be respectively R ₁ ⁺with R ₁ ^-corresponding element.

The computing formula of approach degree analysis is

$C_i^{+}=D_i^{-}/(D_i^{+}+D_i^{-})(0\&le;C_i^{+}\&le;1)$

When judge object is positive ideal solution, C _i ⁺=1, when judge object is minus ideal result, C _i ⁺=0, generally pass judgment on object approach degree C _i ⁺value is (0,1), reflects and passes judgment on the degree that object presses close to positive ideal solution.

(5) AHP-TOPSIS scoring model

Construct Judgement Matrix by the approach degree analysis of TOPSIS method, in conjunction with the weight that AHP method calculates, passing judgment on object Comprehensive Evaluation result vector Q is

Q＝W×C

In formula: C is the Judgement Matrix that the approach degree of each judge object and positive ideal solution is formed, W is the rule layer weight that AHP method calculates.

Concrete, in the present embodiment, the concrete steps of step 4 are as follows:

The Primary Judgement Matrix of three class influence factors is set up respectively according to difficulty of construction grade evaluation criterion and grade of difficulty criterion:

A. geologic condition: $P=\left[\begin{array}{ccccc}10& 1.5& 2& 10& 5\\ 20& 4.5& 4& 20& 3\\ 30& 7.5& 6& 30& 1\\ 26.6& 7.86& 6.13& 46.7& 1.92\end{array}\right]$

In geologic condition, the distribution of soil thickness, bedrock relief, soil body homogeneity and Coral Reef Rock belongs to expendable index, is worth the smaller the better; Severely-weathered layer distribution belongs to rentability index, and value is the bigger the better.Calculate the distance of difficulty of construction opinion rating and positive ideal solution and minus ideal result and corresponding approach degree, as shown in table 11:

Table 11 geologic condition total hierarchial sorting result

Grade of difficulty	Di +	Di -	Ci +	Sequence
					N 1	0.289	0.118	0.290	1
N 2	0.199	0.121	0.379	2
					N 3	0.157	0.211	0.574	3
N	0.091	0.290	0.761	4

B. preparation of construction condition: $P=\left[\begin{array}{cccc}7.00& 7.00& 7.00& 7.00\\ 3.00& 3.00& 3.00& 3.00\\ 1.00& 1.00& 1.00& 1.00\\ 8.00& 7.50& 8.50& 7.20\end{array}\right]$

Preparation of construction all belongs to expendable index, is worth the smaller the better; Severely-weathered layer distribution belongs to rentability index, and value is the bigger the better.Calculate the distance of difficulty of construction opinion rating and positive ideal solution and minus ideal result and corresponding approach degree, as shown in table 12:

Table 12 preparation of construction total hierarchial sorting result

Grade of difficulty	Di +	Di -	Ci +	Sequence
					N 1	0.133	0.017	0.112	2
N 2	0.044	0.104	0.701	3
					N 3	0.000	0.148	1.000	4
N	0.148	0.000	0.000	1

C. working measure condition: $P=\left[\begin{array}{cccc}7.00& 7.00& 7.00& 7.00\\ 3.00& 3.00& 3.00& 3.00\\ 1.00& 1.00& 1.00& 1.00\\ 8.50& 8.20& 7.50& 7.40\end{array}\right]$

Working measure all belongs to expendable index, is worth the smaller the better; Severely-weathered layer distribution belongs to rentability index, and value is the bigger the better.Calculate the distance of difficulty of construction opinion rating and positive ideal solution and minus ideal result and corresponding approach degree, as shown in table 13:

Table 13 working measure total hierarchial sorting result

Grade of difficulty	Di +	Di -	Ci +	Sequence
					N 1	0.081	0.008	0.088	2
N 2	0.027	0.061	0.694	3
					N 3	0.000	0.088	1.000	4
N	0.088	0.000	0.000	1

D. with AHP-TOPSIS scoring model prediction difficulty of construction grade forecast

The weight of each judging quota of the rule layer calculated by AHP method is:

W＝[0.594 0.249 0.157]

The Judgement Matrix of each judging quota approach degree structure obtained according to TOPSIS method is:

$C=\left[\begin{array}{cccc}0.290& 0.379& 0.574& 0.761\\ 0.112& 0.701& 1.000& 0.000\\ 0.088& 0.694& 1.000& 0.000\end{array}\right]$

Then evaluation result vector Q is:

Q＝W×C＝[0.214 0.508 0.747 0.452]

The Comprehensive Evaluation result that to sum up can obtain each construction difficulty or ease grade is respectively:

N ₁=21.4%, N ₂=50.8%, N ₃=74.7%, N=45.2%, wherein N ∈ (N ₁, N ₂), obtaining difficulty of construction grade by predicting the outcome is N2 (generally).Although the geologic condition in this place is very complicated, difficulty of construction large, predicting the outcome, it is general to be still difficulty of construction, absolutely proves the vital role of preparation of construction and working measure.So must first analyze Geological condition, then for the evaluation result of Geological condition and difficulty of construction, select preparation of construction conditionally, take effective, necessary working measure.That is, can according to the influential effect of each level factor, the arrangement and method for construction of next block Impermeable underground wall curtain body of timely adjustment and/or preparation of construction, evade adverse risk in advance, thus realize bordering on the sea the difficulty of construction dynamic forecasting of regional foundation ditch Impermeable underground wall curtain and adjustment to the South Sea.

Regional foundation pit waterproof curtain design and construction difficulty is bordered on the sea comparatively greatly in the South Sea, comparatively different from the general foundation ditch in interior ground, and present stage is temporarily without good design and construction process, construction costs and the prediction and evaluation method of construction period.Utilize this method can carry out performance prediction to the South Sea typical foundation pit construction difficulty in area that borders on the sea, the arrangement and method for construction of next block Impermeable underground wall curtain body of timely adjustment and/or preparation of construction, evade adverse risk in advance, be convenient to estimate foundation pit waterproof curtain design and construction cost and construction period simultaneously.Difficulty of construction appraisement system of the present invention succinctly facilitates, workable, to the South Sea border on the sea containing coral reef chip stratum construction evaluation have better applicability.

Foregoing description is only the description to present pre-ferred embodiments, any restriction not to the scope of the invention, and any change that the those of ordinary skill in field of the present invention does according to above-mentioned disclosure, modification, all belong to the protection domain of claims.

Claims (7)

1. an Impermeable underground wall curtain body construction difficulty Forecasting Methodology, is characterized in that, comprise the steps:

Step 1, preparation of construction is utilized to carry out an Impermeable underground wall curtain body construction in conjunction with geologic condition on construction ground;

Step 2, the comprehensive each factor analyzing Effect Field ground difficulty of construction, carry out distinguishing hierarchy to described each factor and sort out, forming each construction difficulty or ease grade evaluation criterion for every class factor;

Step 3, utilize APH analytical hierarchy process analyze described each factor, obtain the index weights that each factor affects for difficulty of construction;

Step 4, in conjunction with TOPSIS similarity to ideal solution ranking method, respectively risk class division is carried out to the influence factor of same level according to above-mentioned difficulty of construction grade evaluation criterion, determine the influential effect of each level factor.

2. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 1, is characterized in that, according to the influential effect of each level factor, adjusts arrangement and method for construction and/or the preparation of construction of next block Impermeable underground wall curtain body in time, evades adverse risk in advance.

3. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 1, is characterized in that, the described each factor affecting place difficulty of construction is divided into geologic condition, preparation of construction and working measure three class.

4. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 3, it is characterized in that, described geologic condition comprises the thickness of overburden layer, the homogeneity of upper overburden layer, the fluctuating quantity of bedrock surface, Coral Reef Rock distribution situation and severely-weathered layer distribution situation; Described preparation of construction comprises mixing pile stake machine type, jet grouting pile driving machine, inspecting hole, draws drilling machine and water power standby condition; And working measure comprises examination pore-forming, inspecting hole, draws hole and lower pipe.

5. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 3, it is characterized in that, described construction site is positioned at borders on the sea containing Coral Reef Rock area, geologic structure is from top to bottom followed successively by: containing coral reef chip soil layer, severely-weathered layer and middle waste mantle, and described Impermeable underground wall curtain body adopts the combined enclosure form of three axes agitating pile and high-pressure rotary jet grouting pile on vertical section.

6. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 5, it is characterized in that, the construction procedure of described Impermeable underground wall curtain body comprises:

Step 11, carries out examination pile to construction site, tentatively determines the construction parameter of three axes agitating pile and high-pressure rotary jet grouting pile;

Step 12, adopts rig to carry out inspecting hole, verifies the bedrock surface buried depth situation containing the Coral Reef Rock depth of stratum in the soil layer of Coral Reef Rock, severely-weathered layer thickness and middle waste mantle;

Step 13, for containing the soil layer of Coral Reef Rock and severely-weathered layer, adopt single cover to make three axes agitating pile stake machine and construct, three axes agitating pile injection is to the above 1.0-1.5m degree of depth of bedrock surface;

Step 14, carries out drawing hole, draws more than 1m under hole to bedrock surface after three axes agitating pile has been constructed, can whole hole after guaranteeing to enter basement rock projected depth, and pore-forming aperture is not less than 130mm, and perpendicularity deviation is not more than 1/200, and the biased difference in hole is not more than 20mm;

Step 15, it is complete with down tube to draw hole, and adopt pvc pipe, by pvc pipe back cover, interior mud grouting, transfers more than 1m to bedrock surface from drawing hole;

Step 16, utilizes jet grouting pile driving machine construction high-pressure rotary jet grouting pile, enter bedrock surface more than 1.0 meters under high-pressure rotary jet grouting pile, high-pressure rotary jet grouting pile and three axes agitating pile effectively overlap more than 1.0 meters.

7. Impermeable underground wall curtain body construction difficulty Forecasting Methodology as claimed in claim 6, is characterized in that, in step 15, if the sludge of precipitation is thicker at the bottom of hole, necessary clear hole deslagging, guarantees that pvc pipe enters below bedrock surface more than 1.0m.