A Life Cycle Sustainability Assessment Framework for Geotechnical Engineering

ERC Team Members

CBBG Faculty

Alissa Kendall, UC Davis

Other Research Staff

Graduate Students

Alena Raymond

James Tipton

Undergraduate Students

Project Goals

The goal of this project is to develop a life cycle sustainability assessment (LCSA) framework for

geotechnical engineering and to apply this framework to CBBG projects to encourage

sustainability-oriented innovation in geotechnical solutions.

The project's role in support of the strategic plan

The LCSA framework is used to inform CBBG project selection and to guide innovation as

projects mature through each of the 3-planes (i.e., fundamental knowledge, enabling technologies,

and systems). The LCSA framework is also a mechanism for industry engagement through the

development of benchmark LCSAs, which include cost assessments. Industry partners also inform

assessment of feasibility and cost for proposed technologies (once research and development is

sufficiently mature) as part of the LCSA process.

Fundamental Research, Education, or Technology Advancement Barriers

Fundamental research questions that must be answered to develop a standardized LCSA approach

for evaluation of geotechnical systems include: 1) what is the appropriate scope and methods for

environmental life cycle assessment (ELCA) of geotechnical systems; and 2) what level of detail

and predictive capabilities are required for robust analysis outcomes at the research and

development stage of technology development. Barriers to advancing this research include: 1) the

maturity of CBBG projects, which affect the availability of data and information required for

LCSA of a given technology; 2) the development of a life cycle inventory database and modeling

approach to streamline assessment; and 3) collecting estimates of damage costs for pollutants to

provide a mechanism for including pollution damage costs (i.e., externalities) in life cycle cost

analysis (LCCA).

Any research aspect that involves foreign collaborations, especially indicating the length of

time US faculty or students spent abroad conducting their work, and vice versa, and the

value added of that work to the student’s/faculty’s work.

None to report.

Achievements in previous years

1) Development, piloting, and dissemination of LCSA Questionnaire for CBBG project

proposals.

2) Development of two Example LCSA Questionnaires for instructive purposes.

3) Completion of a comprehensive literature review of LCSA in the geotechnical field (with

a focus on ELCA) to provide a critical review on the state of the practice, identify gaps,

and propose best practices for ELCA in the geotechnical engineering field. A manuscript

for peer review was submitted in 2016.

Achievements in past year 1) Revision and refinement of LCSA Questionnaire, which is now CBBG Annual Project

Evaluation Report 2: Life Cycle Sustainability Assessment (Report 2). Development of a

standardized approach to rating and feedback of submitted Report 2s, entitled Summary

LCSA Evaluation Statement (referred to as “Outcomes Memo” in last year’s project report).

2) Completion of evaluation for all submitted Report 2s. This included two quantitative

ELCAs for projects with enough data and information to support quantitative analysis

(MICP and root-inspired foundations), and qualitative evaluations of all other submitted

projects.

3) Acceptance and online publication of one peer-reviewed journal paper entitled “Review

of life-cycle-based environmental assessments of geotechnical systems”

(http://dx.doi.org/10.1680/jensu.16.00073). This article critically reviews the body of

previous work on LCA applied to geotechnical systems through a parametric assessment,

summarizing the state-of-the-practice, identifying the sources of uncertainty and

variability that lead to divergent results and conclusions, and developing

recommendations for future LCAs of geotechnical systems. Table 1 below summarizes

our findings with respect to previous studies, and illustrates the limited number of

infrastructure types assessed and the relatively small number of peer-reviewed studies

that have been published:

Table 1. Summary of Identified Literature of LCA applied to Geotechnical Systems Study

No.

Primary

Author

Year Publication

Type

Peer

Reviewed

Infrastructure

Type

Region of

Study

Assessment

Method

1 Chau 2008 CP No RW UK Process-Based

2 Storesund 2008 CP No RW US EIO-LCA

3 Rafalko 2010 CP No MSE RW US Process-Based

4 Inui 2011 JA Yes RW UK Process-Based

5 Soga 2011 JA Yes RW UK Lit. Review

6 Lee 2015 CP No MSE RW -- Process-Based

7 Giri 2015 CP No RW US Process-Based

8 Damians 2016 JA Yes RW -- Process-Based

9 Phillips 2016 CP No RW US Process-Based

10 Misra 2010 MT Yes DF -- Process-Based

11 Giri 2014 CP Yes DF US Process-Based

12 Spaulding 2008 CP No GI US, AU Process-Based

13 Pinske 2011 MT Yes GI US Process-Based

14 Shillaber 2015b JA Yes GI US Hybrid LCA

15 Walker 2014 CP No Other UK, DE, DK Lit. Review

16 Chau 2012 JA Yes Other UK Process-Based

Note: CP = conference paper; JA = journal article; MT = Master’s thesis; RW = retaining wall; MSE = mechanically

stabilized earth; DF = deep foundation; GI = ground improvement; UK = United Kingdom; US = United States; AU

= Australia; DE = Germany; DK = Denmark

Figure 1 describes the sources of variability and uncertainty in LCAs of geotechnical

systems. Though some of these sources are common in LCAs of many types of systems,

the site-specific nature of geotechnical solutions is a particular challenge for LCA.

Figure 1. Sources of Variability and Uncertainty in Geotechnical LCA

4) Acceptance and online publication of one conference paper entitled “Life-Cycle

Assessment of Ground Improvement Alternatives for the Treasure Island, California,

Redevelopment” (https://doi.org/10.1061/9780784480434.037) and accompanying

presentation by Alena Raymond at the Geotechnical Frontiers 2017 conference in

Orlando, Florida. This study compared the environmental and economic impacts of five

ground improvement methods for the possible redevelopment of Treasure Island in San

Francisco, California. For each improvement method, the study used LCA to assess the

energy, global warming potential, acidification potential, smog formation potential,

project cost, and social cost of carbon. The scope of analysis is illustrated in Figure 2.

Figure 2. System Definition and Boundary of the Analysis

The study concluded that the most environmentally preferable combination of ground

improvement methods does not include deep soil mixing, as illustrated in the comparison

of scenarios in Table 2.

Table 2. Treasure Island Ground Improvement Scenario Analysis Ground Improvement

Method

Proposed

(ENGEO 2011)

Alternative

1

Alternative

2

Alternative

3

Alternative

4

Deep Soil Mixing 10.4% -- -- -- 10.4%

Vibro Replacement -- 10.4% 10.4% 10.4% --

Vibro Compaction 9.1% -- 65.0% 9.1% 80.5%

Deep Dynamic Compaction 80.5% 80.5% -- 80.5% --

Earthquake Drains -- 9.1% 24.6% -- 9.1%

Primary Energy (GJ) 447427 158038 279035 122349 543447

GWP (tonnes CO2e) 83047 10834 24512 10067 96187

AP (tonnes SO2e) 200 1 61 36 210

Smog (tonnes O3e) 5308 40 1692 974 5606

SCC - 3% Avg ($) $3,737,099 $487,546 $1,103,023 $453,003 $4,328,401

5) Initiation of research for a second peer-reviewed journal article focusing on a critical

review of environmental impact indicators for ELCA applied to geotechnical systems and

technologies.

Summary of other relevant work being conducted within and outside of the ERC and how

this project is different

Related work outside of the ERC is being conducted at UC Davis and elsewhere to develop a

framework and guidelines for ELCA of related systems, such as pavements and complete streets.

However, the pavement ELCA guidelines do not include the full scope of the LCSA (only

environmental impacts, and not economic or social impacts), and cannot inform indicator

development for geotechnical systems based on our critical review of the literature and existing

guidelines. The work on complete streets includes environmental, economic and social

components of sustainability within an LCA framework, which is aligned with the goals of the

ERC LCSA process. However, the social and economic impacts of complete streets are not similar

to those of geotechnical systems. Exploring indicators of social and economic impact for any

infrastructure system could inform future indicator selection for geotechnical projects; however,

the overlap is likely to be minimal as many of the impacts related to, for example, road and street

infrastructure are the result of how the infrastructure is directly used by people, and most

geotechnical systems are not directly used in the same way.

Plans for the next year

The following developments are planned for next year:

1) LCSA Questionnaire (now Report 2) dissemination and creation of Summary LCSA

Evaluation Statement for all CBBG projects.

2) Continue development of a streamlined quantitative ELCA model for proposed projects.

3) Collaborate with industry to develop benchmarks of impacts of conventional ground

improvement technologies for comparison with new biogeotechnologies (both for ELCA

and LCCA).

4) Collect damage cost estimates for pollutants of interest.

5) Environmental sustainability indicator development (critical review of existing indicators

and proposal of new/appropriate indicators for geotechnical technologies/projects).

6) Manuscript development and submission for environmental sustainability indicators for

geotechnical technologies/projects.

7) Continuing to develop MICP ELCA model and evaluation of waste product scenarios for

treatment.

Expected milestones and deliverables for the project

By the end of year three we expect to have an additional manuscript submitted for peer review

addressing environmental sustainability indicators for geotechnical systems/projects. In addition,

we will further refine Report 2 and revise the Summary LCSA Evaluation Statements for all CBBG

projects. By the end of year five we expect to provide a database or tool for industry partners that

documents the costs and environmental impacts of a suite of geotechnical solutions (both CBBG

technologies and comparable alternatives that are commonly implemented).

Member company benefits

This project develops and implements a framework for evaluating the sustainability of existing

and new geotechnical solutions. This has the potential to integrate LCSA-thinking at the

innovation stage of research and development, where the greatest improvements may be identified.

Member companies may benefit in two ways: 1) by engaging with the LCSA team on feasibility

and cost assessment activities, member companies gain intimate knowledge of the innovative

solutions being explored by CBBG research; and 2) member companies will have access to the

resulting database of costs and environmental impacts associated with the many CBBG

technologies evaluated with LCSA.

If relevant, commercialization impacts or course implementation information

None to report.