CN102735575A - Method for rapidly and simply measuring cement content of cement soil - Google Patents

Abstract

The invention discloses a method for rapidly and simply measuring the cement content of cement soil. The method comprises the following steps that: stirred cement slurry is taken at a construction field and brought back to a laboratory to be sealed and stored inside a soil package; after reaching certain period, on-site core sampling is carried out on a cement stirring column, a high pressure rotary spraying stake and the like at the construction field, a core sample is sealed and brought back to the laboratory, and simultaneously the air exhaust saturation is carried out on the cement slurry sample stored in the laboratory and the core sample taken back from the on-site core sampling; the mass, the volume, the density and the moisture content of each testing sample are tested; the mass of a cement hydration product is calculated according to the fact that the saturated cement soil is composed of three parts, i.e., soil grains, the cement hydration product and free water, and according to a density equation and a volume equation of a saturated cement soil core sample; and the quantity of mixed cement is calculated so as to obtain a cement mixing ratio. The detecting method has the advantages of being easy and reliable in operation and high in operability/of great easiness, high reliability and high operability and the like, and has a wide application prospect.

Description

A kind of fast simple detection method of soil cement cement content

Technical field

The present invention relates to a kind of fast simple detection method of soil cement cement content, is the detection method of cement mixed weights such as a kind of cement mixing pile, high-pressure rotary jet grouting pile.Remedying now can't fast detecting cement content technological gap, and detection means is simple and reliable, and sense cycle is short, has practiced thrift time and financial cost, belongs to the underground works technical field.

Background technology

Excavation of foundation pit in a large amount of underground workss, subway tunnel excavation, skyscraper foundation stabilization, express highway roadbed reinforcing etc. all need be carried out grouting and reinforcing to ground.But it is because not enough on the disguise of underground works and the detection means; Unit in charge of construction often takes jerry way to deal with; Make the many underground workss of China have huge potential safety hazard, even intensity often occurs and cross the low superstructure that makes and serious accidents such as inclination occur.In the engineering practice; Basically just measure the next reflection indirectly of the intensity foundation stabilization construction quality of soil cement at present through the way of getting core; The influence factor that influences intensity is more; Even the intensity of soil cement does not reach designing requirement, can't judge also whether unit in charge of construction exists jerry problem, can't play the effect of direct supervision unit in charge of construction.Press for a kind of fast simple detection method that can detect the soil cement cement content on the engineering.

Summary of the invention

Goal of the invention: the present invention provides a kind of fast simple detection method of soil cement cement content; Can carry out direct and quick determination to the cement mixed weight in the foundation stabilization of engineerings such as underground engineering, highway subgrade, Tunnel Engineering, building lot; And detection means is very simple; Can exercise supervision to Base Consolidation Engineering more effectively, reduce the accident that serious quality safety takes place and produces jerry thing.

Technical scheme: a kind of fast simple detection method of soil cement cement content comprises the steps:

Take by weighing the on-the-spot used grout of 100g when (one) constructing, calculate the wherein mass M of cement according to its water cement ratio ₁And sealing;

(2) when reaching regulation after the length of time, it is saturated that the cement product of sealing is bled, and tests its volume V ₁, and the cement product of sealing taken out oven dry and measure its mass M ₂Thereby, can obtain the hydrated cementitious product particle proportion ρ in the corresponding length of time _Cp=M ₁/ [V ₁-(M ₁-M ₂)/ρ _w], cement quality accounts for cement product ratio a=M ₁/ M ₂, ρ _wRepresent the density of water;

(3) scene get core and then and there the sealing take back the laboratory, bleed saturated after, gross mass M, cumulative volume V, the core density p of testing saturated core; And carry out geotechnological water percentage test, test the quality M in the saturated core _w

(4) saturated core is made up of hydrated cementitious product, soil particle and free water three, and its quality and volume are respectively this three kinds of material sums.Then the density of saturated core and volume can be expressed from the next:

$\left(\begin{array}{c}\mathrm{\ρ}=\frac{M_w+{\mathrm{\ρ}}_s{V}_s+{\mathrm{\ρ}}_{\mathrm{cp}}{V}_{\mathrm{cp}}}{V}\\ V=V_s+V_{\mathrm{cp}}+M_w/{\mathrm{\ρ}}_w\end{array}\right)---\left(2\right)$

ρ represents the actual density of saturated core in the formula; M _wRepresent the quality of water in the core; ρ _sRepresent the density of dry ground in the core, can get 2650-2700kg/m usually according to geology exploration report value ³V _sRepresent the volume of dry ground in the core; ρ _CpRepresent the severe of cement product in the core, if use portland cement, be 28d its length of time, common desirable 2900kg/m ³, otherwise need the laboratory build-in test; V _CpRepresent volume, the ρ of cement product in the core _wRepresent the density of water, get 1000kg/m ³

Can calculate the volume V of cement product through formula (2) _Cp, the mass M of hydrated cementitious product _Cp=ρ _CpV _Cp, the cement mixing content M in the core volume then _c=α M _Cp, cement output can obtain the cement mixed ratio of core divided by the core quality.

As do not have the working-yard grout and detect data, then can be similar to by following method value: ρ _Cp=2900kg/m ³, a=0.787, in the substitution formula (1), repeat above-mentioned processing step (four), can obtain the cement mixed ratio of core.

Beneficial effect: compared with prior art; The fast simple detection method of soil cement cement content provided by the present invention; Have weak point detection time, simple, the low cost and other advantages of equipment needed thereby, can supervise more effectively and the behavior of standard construction enterprise construction, guarantee the quality safety of various underground workss better; Avoid not reaching designing requirement, be compelled to mend stake and incur loss through delay economic losses such as duration because of the cement mixed weight deficiency causes cement mixing pile intensity.

Embodiment

Below in conjunction with specific embodiment; Further illustrate the present invention; Should understand these embodiment only be used to the present invention is described and be not used in the restriction scope of the present invention; After having read the present invention, those skilled in the art all fall within the application's accompanying claims institute restricted portion to the modification of the various equivalent form of values of the present invention.

Embodiment 1:

Certain subway shield end well is reinforced and is adopted three mixing piles, and the soil layer of shield structure acrossing range is hard cohesive soil, strict control cement mixed ratio 20% during construction, and on-the-spot water intaking mud maintenance 28d bleeds saturated, test M ₁=100g, M ₂=78.9g, a=M ₂/ M ₁=0.789.Three mixing piles are got the core mass M=805.4g after saturated behind the core, the mass M of water in the core behind the 28d _w=355.9g, core volume V=475.6cm ³, core actual density ρ=1.693g/cm ³, bringing formula (2) into, to obtain cement mixed ratio be 20.3%, very approaching with the volume of reality.

Embodiment 2:

Certain highway foundation is reinforced and is adopted the rotary churning pile stake, and it reinforces the figure layer is silty clay, strict control cement mixed ratio 15% during construction, and it is saturated to bleed behind the on-the-spot water intaking mud maintenance 90d, test M ₁=100g, M ₂=76.9g, a=M ₂/ M ₁=0.769.Three mixing piles are got the core mass M=813.3g that bleeds behind the core after saturated, the mass M of water in the core behind the 90d _w=260.3g, core volume V=464.1cm ³, core actual density ρ=1.753g/cm ³, bring formula (2) into and obtain grout and mix than 14.1%, approaching with the volume of reality.

Claims (2)

1. the fast simple detection method of a soil cement cement content is characterized in that, comprises the steps:

Step 1 takes by weighing the on-the-spot used grout of 100g during construction, calculate the wherein mass M of cement according to its water cement ratio ₁And sealing;

Step 2, when reaching regulation after the length of time, it is saturated that the cement product of sealing is bled, and tests its volume V ₁, and the cement product of sealing taken out oven dry and measure its mass M ₂Thereby, obtain the hydrated cementitious product particle proportion ρ in the corresponding length of time _Cp=M ₁/ [V ₁-(M ₁-M ₂)/ρ _w] (1), cement quality accounts for cement product ratio a=M ₁/ M ₂, ρ _wRepresent the density of water;

Step 3, scene get core and then and there the sealing take back the laboratory, bleed saturated after, gross mass M, cumulative volume V, the core density p of testing saturated core; And carry out geotechnological water percentage test, test the quality M in the saturated core _w

Step 4, saturated core is made up of hydrated cementitious product, soil particle and free water three, and its quality and volume are respectively this three kinds of material sums; Then the density of saturated core and volume are expressed from the next:

$\left(\begin{array}{c}\mathrm{\ρ}=\frac{M_w+{\mathrm{\ρ}}_s{V}_s+{\mathrm{\ρ}}_{\mathrm{cp}}{V}_{\mathrm{cp}}}{V}\\ V=V_s+V_{\mathrm{cp}}+M_w/{\mathrm{\ρ}}_w\end{array}\right)---\left(2\right)$

ρ represents the actual density of saturated core in the formula; M _wRepresent the quality of water in the core; ρ _sRepresent the density of dry ground in the core, get 2650-2700kg/m ³V _sRepresent the volume of dry ground in the core; ρ _CpRepresent the severe of cement product in the core, if use portland cement, be 28d its length of time, gets 2900kg/m ³, otherwise need the laboratory build-in test; V _CpRepresent volume, the ρ of cement product in the core _wRepresent the density of water, get 1000kg/m ³

Calculate the volume V of cement product through formula (2) _Cp, the mass M of hydrated cementitious product _Cp=ρ _CpV _Cp, the cement mixing content M in the core volume then _c=α M _Cp, cement output promptly obtains the cement mixed ratio of core divided by the core quality.

2. the fast simple detection method of soil cement cement content as claimed in claim 1 is characterized in that: detect data like no working-yard grout, and then approximate by following method value: ρ _Cp=2900kg/m ³, a=0.787, in the substitution formula (1), repeating said steps four promptly obtains the cement mixed ratio of core.